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Complete Examination 
Questions and Answers for 
Marine and Stationary Engineers 


A Complete Engine Operator’s Catechism 


Giving the Latest and Most Approved Answers to all Leading Questions which 
will be Asked for the Purpose of Examining and Determining the Quali¬ 
fications of Applicants for Licenses for Engineers and for Persons 
having Charge of Steam Boilers as Approved by all Muni¬ 
cipalities and Government Boards of Examining 
Engineers, both Stationary and Marine 


Special Reference to Modern 


Types of Oil Engines 


BY 

CALVIN F. SWINGLE, M.E. 

11 

Author of Twentieth Century Hand-Book for Steam Engineers 
and Electricians“Modern Locomotive Engineering 
Hand-Book“Steam Boilers: Their Con¬ 
struction, Care and OperationEtc. 


ILLUSTRATED 


m ■ 

CHICAGO 

FREDERICK J. DRAKE & CO. 

PUBLISHERS 
















Copyright 1906 
By 

Frederick J. Drake & Co. 


Copyright 1914 
By 

Frederick J. Drake & Co. 


Copyright 1917 
By 

Frederick J. Drake & Co. 



©CU467001 

''l l l 







CONTENTS 

CHAPTER I 

PAGE 


m, Heat, Combustion and Fuels. 7 

CHAPTER II 

The Boiler. 25 

CHAPTER III 

Boiler Construction . 65 

CHAPTER IV 

Boiler Settings and Appurtenances. 81 

CHAPTER V 

Boiler Operation .128 

CHAPTER VI 

Types of Engines—Classification.173 

CHAPTER VII 

Condensers—Air-Pumps—Sea-Water .211 

j CHAPTER VIII 

Auxiliary Machinery and Fittings.240 

CHAPTER IX 

The Indicator—Principles of the Indicator.270 

CHAPTER .X , 

The Steam Turbine—Fundamental Principles.304 

CHAPTER XI 

Modern Types of Oil Engines.361 















INTRODUCTION 


The development of the science of steam engineering 
and the continually increasing demand for more power 
for manufacturing purposes and for transportation, both > 
on land and sea, have in these modern times resulted in 
the creation of power plants, which are truly marvelous 
in their details when compared with the steam machinery 
of forty years ago. Even the last twenty years have 
witnessed tremendous developments along these lines, and 
we may imagine the effect it would have upon an 
engineer, who twenty years ago was counted as first class 
in his business, but who, having taken a Rip Van Winkle 
sleep of twenty years, is suddenly awakened and finds him¬ 
self set down in the engine room of a first-clas^ocean 
steamer, or in the midst of one of our modern up-to-date 

power plants. The facts are, he would have hard work 

* 

to recognize his surroundings. Even the steam gaugee 
would indicate a pressure of 150 to 175 pounds more per 
square inch than did the old-time gauges. Therefore, in 
view of the remarkable improvements in steam machinery 
which have been made and are continually being made, it 
certainly behooves engineers to do their utmost to keep 
step with the march of progress. The author has endeav¬ 
ored, in the following pages, to place before his readers 
information in a catechetical form which will be found tc 
cover all of the various details appertaining to the opera¬ 
tion of modern steam plants, both stationary and marine. 

C. F. S. 








CHAPTER I 


• ' • * , J 5 y , • . 

STEAM, HEAT, COMBUSTION, AND FUELS 

Ques. 1.—What is steam? 

Ans.—Steam is vapor of water. 

Ques. 2.—At what temperature will water evaporate 
(boil) in the open air at sea level? 

Ans.—212 degrees Fahrenheit. 

Ques. 3.—If 1 cubic foot of water is evaporated at 
212 degrees into steam at atmospheric pressure, how 
many cubic feet of steam will there be? In other words, 
what will the volume of the steam be? 

Ans.—1,646 cubic feet. 

Ques. 4.—Then what is the relative volume of steam 
at atmospheric pressure, and the water from which it was 
evaporated at 212 degrees? 

Ans.—1,646 to 1. 

Ques. 5.—What is the relative volume of steam at 
200 pounds gauge pressure, and the water from which it 
was generated? 

Ans.—132 to 1. 

Ques. 6.—What is meant by the terms atmospheric 
pressure, gauge pressure, and absolute pressure, as 
applied to steam and other gases? 

Ans.—The pressure in pounds exerted by the steam, 
or gas, on each square inch of the interior surface of the 
containing vessel, tending to rupture it. 

7 


8 


QUESTIONS AND ANSWERS 


Ques. 7.—What is vacuum? 

Ans.—The absence of all pressure in the interior of a 
vessel. 

Table 1, which follows, shows the physical properties 


of saturated steam from a perfect vacuum up to 1,000 


pounds absolute pressure. It will be found convenient 1 


for reference. 




TABLE I 

Properties of Saturated Steam 


Vacuum 

Inches of Mercury 

Absolute 

Pressure 

Lbs. per Sq. Inch 

Temp. 

Degrees F. 

Total Heat 
above 32 0 F. 

Latent Heat 

H-h 

Heat units 

Relative Volume 

Cubic Feet in 

1 Lb. Wt. of Steam 

Wt. of 1 Cubic Foot 

of Steam, Lbs. 

In the Water 
h 

Heat-units 

In the Steam 

H 

Heat-units 

29-74 

089 

32 . 

O. 

1091.7 

1091.7 

208,080 

3333-3 

'P - 

.0005 

29.67 

-122 

40. 

8. 

1094.1 

I086.1 

154,330 

2472.2 

.0004 

29. 56 

.176 

50 . 

18. 

1097.2 

IO79.2 

107,630 

I724.I 

.0006 

29.40 

.254 

60. 

28.01 

1100.2 

IO72.2 

76,370 

1223.4 

.0008 

29.19 

♦ 359 

70 . 

38.02 

1103.3 

1065.3 

54,660 

875.61 

.0011 

28.90 

.502 

80. 

48.04 

1106.3 

1058.3 

39,690 

635.80 

.0016 

28.51 

.692 

90. 

58.06 

I109.4 

1051.3 

20,290 

469.20 

.0021 

28.00 

•943 

IOO. 

68.08 

1112.4 

I044.4 

21,830 

349.70 

.0028 

27.88 

I. 

102.1 

70.09 

1113.1 

IO43.O 

20,623 

334.23 

.0030 

25.85 

2. 

126.3 

94.44 

1120.5 

1026.0 

10,730 

I 7>23 

.0058 

23.83 

3 - 

141.6 

109.9 

1125.1 

1015.3 

7,325 

118.00 

.0085 

21.78 

4- 

I 53 -I 

121.4 

1128.6 

IOO7.2 

5,588 

89.80 

.0111 

19.74 

5* 

162.3 

130.7 

1131-4 

1000.7 

4,530 

72.50 

.0137 

17.70 

6. 

170.1 

138.6 

1133.8 

995-2 

3,816 

6I.IO 

.0163 

15.67 

7 - 

I76.9 

145.4 

1135.9 

990.5 

3,302 

53.00 

.0189 

13.63 

8. 

I82.9 

I 5 I .5 

H 37-7 

986.2 

2,912 

46.60 

.0214 

II.60 

9 - 

188.3 

156.9 

H 39-4 

982.4 

2,607 

41.82 

.0239 

9-56 

10. 

193.2 

161.9 

1140.9 

979.0 

2,361 

37.80 

.0264 

7.52 

11. 

197.8 

166.5 

1142.3 

975-8 

2,159 

34.61 

.0289 

5-49 

12. 

202.0 

170.7 

1143.5 

972.8 

1,990 

31.90 

.0314 

3-45 

13. 

205.9 

174-7 

1144.7 

970.0 

1,846 

29.60 

.0338 

1.41 

14. 

209.6 

178.4 

1145.9 

967.4 

1,721 

27.50 

.0363 

0.00 

14.7 

212.0 

180.9 

1146.6 

965.7 

1,646 

26.36 

.0379 


























STEAM, HEAT, COMBUSTION, AND FUELS 


9 


Table I —Contmued 


Gauge Pressure 
Lbs. per Sq. In. 

Absolute Pressure 
Lbs. per Sq. In. 

Temp. 

Degrees F. 

Total Heat 
Above 32 0 F. 

Latent Heat 

H-h 

Heat-units 

Relative Volume 

Cubic Feet in 

1 Lb. Wt. of Steam 

Wt. of 1 Cubic Foot 

of Steam, Lbs. 

In the Water 
h 

Heat-units 

In the Steam 

H 

Heat-units 

0-3 

15 

213-3 

181.9 

II46.9 

965-0 

1,614 

25.90 

.0387 

1-3 

16 

216.3 

185.3 

1147.9 

962.7 

U 5 I 9 

24-33 

.0411 

2.3 

17 

219.4 

188.4 

1148.9 

960.5 

1,434 

23.OO 

-043 5 

3-3 

18 

222.4 

I 9 I -4 

1149.8 

958.3 

1,359 

21.80 

.0459 

4-3 

19 

225.2 

194.3 

1150.6 

956.3 

1,292 

20.70 

.0483 

5-3 

20 

227.9 

197.O 

II 5 I .5 

954-4 

1,231 

19.72 

.0507 

6-3 

21 

230.5 

199.7 

II52.2 

952.6 

1,176 

18. 84 

.0531 

7-3 

22 

233-0 

202.2 

1153.0 

950.8 

1,126 

18.03 

-0555 

8-3 

23 

235.4 

204.7 

II 53.7 

949-1 

1,080 

17.30 

.0578 

9-3 

24 

237.8 

207.0 

II 54.5 

947-4 

1,038 

16.62 

.0602 

10.3 

25 

240.0 

209.3 

1155.1 

945.8 

998 

16.00 

.0625 

11 .3 

26 

242.2 

2 II .5 

1155.8 

944-3 

962 

15.42 

.0649 

12.3 

27 

244 3 

213.7 

1156.4 

942.8 

929 

14.90 

.0672 

13.3 

28 

246.3 

215.7 

H 57 -I 

941.3 

898 

14.40 

.0696 

14.3 

29 

248.3 

217.8 

H 57-7 

939-9 

869 

13.91 

.0719 

15.3 

30 

250.2 

219.7 

1158.3 

938.9 

841 

13.50 

.0742 

16.3 

31 

252.I 

221.6 

1158.8 

937-2 

816 

13.07 

.0765 

17.3 

32 

254.0 

223.5 

II 59.4 

935.9 

792 

12.68 

.0788 

18.3 

33 

255.7 

22 5.3 

II 59.9 

934-6 

769 

12.32 

.0812 

19-3 

34 

257.5 

227.1 

1160.5 

933.4 

748 

12.00 

.0835 

20.3 

35 

259.2 

228.8 

1161.0 

932.2 

728 

11.66 

.0858 

21.3 

36 

260.8 

230.5 

1161.5 

931.0 

709 

11.36 

.0880 

22.3 

37 

262.5 

232.1 

1162.0 

929.8 

691 

11.07 

.0903 

23 3 

38 

264.0 

233.8 

1162.5 

928.7 

674 

10.80 

.0926 

24.3 

39 

265.6 

235.4 

1162.9 

927.6 

658 

10.53 

.0949 

25.3 

40 

267.1 

236.9 

1163.4 

926.5 

642 

10.28 

.0972 

26.3 

4 i 

268.6 

238.5 

1163.9 

925.4 

627 

10.05 

.0995 

27.3 

42 

270.I 

240.0 

1164.3 

924.4 

613 

9. 8 3 

.1018 

28.3 

43 

271.5 

24I.4 

1164.7 

923.3 

600 

9.61 

.1040 

29-3 

44 

272.9 

242.9 

1165.2 

922.3 

587 

9.41 

.1063 

30.3 

45 

274.3 

244-3 

1165.6 

921.3 

575 

9.21 

.1086 

31.3 

46 

275.7 

245.7 

1166.0 

920.4 

563 

9.02 

.1108 

32.3 

47 

277.O 

247.0 

1166.4 

919.4 

552 

8.84 

.1131 

33-3 

48 

278.3 

248.4 

1166.8 

918.5 

54 i 

8.67 

.1153 

34-3 

49 

279.6 

249.7 

1167.2 

917.5 

53 i 

8.50 

.1176 

35-3 

50 

280.9 

251.0 

1167.6 

916.6 

520 

8-34 

.1198 

36.3 

5 i 

282.1 

252.2 

1168.0 

915.7 

5 ii 

8.19 

.1221 

37-3 

52 

283.3 

253.5 

1168.4 

9 r 4-9 

502 

8.04 

.1243 






























8 


QUESTIONS AND ANSWERS 


Ques. 7 .—What is vacuum? 

Ans.—The absence of all pressure in the interior of a 
vessel. 

Table 1, which follows, shows the physical properties 
of saturated steam from a perfect vacuum up to 1,0003 
pounds absolute pressure. It will be found convenient 
for reference. 


TABLE I 

Properties of Saturated Steam 


►> 

-C 


Total 

Heat 


<y 

6 

•*» 

O 

Ui 

S3 

O 

Absolute 
Pressure 
Lbs. per Sq. Inc' 

Temp. 
Degrees F. 

above 32 0 F. 

cu 

a 

3 

c g 

O • 

fc .2 

Vacuum 
Inches of Mei 

In the Water 
h 

Heat-units 

In the Steam 

H 

Heat-units 

Latent He 
H-h 

Heat unit 

r—t 

O 

> 

0 ) 

> 

'+3 

41 

Pi 

£ 0 

“d 

M 

x > - 

= s 

CJ cfl 

o W 

- 0 
£ 

29-74 

089 

32 . 

O. 

1091.7 

1091.7 

208,080 

3333-3 

.0005 

29.67 

.122 

40 . 

8. 

IO94.1 

1086.1 

154.330 

2472.2 

.0004 

29.56 

.176 

50 . 

18. 

IO97.2 

1079.2 

107,630 

1724.1 

.0006 

29.40 

.254 

60. 

28.01 

1100.2 

IO72.2 

76,370 

1223.4 

.0008 

29.19 

•359 

70 . 

38.02 

1103.3 

1065.3 

54.660 

875.61 

.OOII 

28.90 

.502 

80. 

48.04 

1106.3 

1058.3 

39,690 

635.80 

.0016 

28.51 

.692 

90. 

58.06 

1109.4 

1051.3 

20,290 

469.20 

.0021 

28.00 

•943 

IOO. 

68.08 

1112.4 

1044.4 

21,830 

349.70 

.0028 

27.88 

I. 

102.1 

70.09 

1113.1 

1043.0 

20,623 

334-23 

.OO3O 

25.85 

2. 

126.3 

94-44 

1120.5 

1026.0 

10,730 

173-23 

.OO58 

23.83 

3- 

141.6 

109.9 

1125.1 

1015.3 

7,325 

118.00 

,.0085 

.0111 

21.78 

4 - 

I 53 .I 

121.4 

1128.6 

1007.2 

5,588 

89.80 

19.74 

5 ‘ 

I62.3 

130.7 

1131.4 

1000.7 

4.530 

72.50 

.0137 ; 

17.70 

6. 

170.1 

138.6 

1133.8 

995-2 

3,816 

61.10 

.0163 

15.67 

7 - 

I76.9 

145.4 

II 35.9 

990.5 

3.302 

53-00 

.0189 

I 3.63 

8. 

182.9 

I 5 I .5 

II 37.7 

9S6.2 

2,912 

46.60 

.0214 

II.60 

9 - 

188.3 

156.9 

U 39-4 

982.4 

2,607 

41.82 

.0239 

9.56 

10. 

193.2 

161.9 

1140.9 

979.0 

2,361 

37 . 8 o 

.0264 

7-52 

11. 

197.8 

166.5 

1142.3 

975-8 

2,159 

34.6i 

.0289 

5-49 

12. 

202.0 

170.7 

H 43-5 

972.8 

1,990 

31.90 

.0314 

3-45 

13 . 

205.9 

174.7 

1144.7 

970.0 

1,846 

29.60 

.0338 

1.41 

14. 

209.6 

178.4 

1145.9 

967.4 

1,721 

27.50 

.0363 

0.00 

14.7 

212.0 

180.9 

1146.6 

965.7 

1,646 

26.36 

•0379 

























STEAM, HEAT, COMBUSTION, AND FUELS 


Table I— Continued 


Gauge Pressure 
Lbs. per Sq. In. 

Absolute Pressure 
Lbs. per Sq. In. 

Temp. 

Degrees F. 

Tota 

Abov< 

U 

l & 
M 

r- C 3 

4 _» 0 ) 

c = 

Heat 

J 32 0 F. 

g 

5 w 

CT 3 +•» 

flj • 

-*-* 

1 

J 3 

c K 

Latent Heat 

H-h 

Heat-units 

Relative Volume 

Cubic Feet in 

1 Lb. Wt. of Steam 

Wt. of 1 Cubic Foot 

of Steam, Lbs. 

0-3 

15 

213-3 

181.9 

1146.9 

965.0 

1,614 

25.90 

.0387 

1-3 

16 

216.3 

185.3 

1147.9 

962.7 

U 5 I 9 

24-33 

.0411 

2.3 

17 

219.4 

188.4 

1148.9 

960.5 

!»434 

23.00 

.0435 

3-3 

18 

222.4 

I 9 I -4 

1149.8 

958.3 

1,359 

21.80 

.0459 

4-3 

19 

225.2 

194.3 

1150.6 

956.3 

1,292 

20.70 

.0483 

5-3 

20 

227.9 

197.0 

II 5 I .5 

954-4 

1,231 

I9.72 

.0507 

6.3 

21 

230.5 

I99.7 

1152.2 

952.6 

1,176 

18. 84 

.0531 

7.3 

22 

233.0 

202.2 

1153.0 

950.8 

1,126 

18.03 

.0555 

8.3 

23 

235.4 

204.7 

II 53.7 

949-1 

1,080 

17.30 

.0578 

9-3 

24 

237.8 

207.0 

II 54.5 

947-4 

1,038 

16.62 

.0602 

10.3 

25 

240.0 

209.3 

1155.1 

945-8 

998 

16.00 

.0625 

11 .3 

26 

242.2 

2II.5 

1155.8 

944-3 

962 

15.42 

.0649 

12.3 

27 

244-3 

213.7 

1156.4 

942.8 

929 

14.90 

.0672 

13.3 

28 

246.3 

215.7 

II 57 .I 

941-3 

898 

14.40 

.0696 

14.3 

29 

248.3 

217.8 

H 57-7 

939.9 

869 

13.91 

.0719 

15.3 

30 

250.2 

219.7 

1158.3 

938.9 

841 

13.50 

.0742 

16.3 

31 

252.1 

221.6 

1158.8 

937.2 

816 

13.07 

•0765 

17.3 

32 

254.0 

223.5 

II 59.4 

935.9 

792 

12.68 

.0788 

18.3 

33 

255.7 

225.3 

II 59.9 

934-6 

769 

12.32 

.0812 

19-3 

34 

257.5 

227.1 

1160.5 

933.4 

748 

12.00 

.0835 

20.3 

35 

259.2 

228.8 

1161.0 

932.2 

728 

11.66 

.0858 

21.3 

36 

260.8 

230.5 

1161.5 

931.0 

709 

11.36 

.0880 

22.3 

37 

262.5 

232.1 

1162.0 

929.8 

691 

11.07 

.0903 

23 3 

38 

264.0 

233.8 

1162.5 

928.7 

674 

10.80 

.0926 

24.3 

39 

265.6 

235.4 

1162.9 

927.6 

658 

10.53 

.0949 

25.3 

40 

267.1 | 

236.9 

1163.4 

926.5 

642 

10.28 

.0972 

26.3 

4 i 

268.6 

238.5 

1163.9 

9254 

627 

10.05 

•0995 

27.3 

42 

270.I 

24O.O 

1164.3 

924.4 

613 

9-83 

.1018 

28.3 

43 

271.5 

24I.4 

1164.7 

923.3 

600 

9.61 

.1040 

29-3 

44 

272.9 

242.9 

1165.2 

922.3 

587 

9.41 

.1063 

30.3 

45 

274.3 

244-3 

1165.6 

921.3 

575 

9.21 

.1086 

31.3 

46 

275.7 

245.7 

1166.0 

920.4 

563 

9.02 

.1108 

32.3 

47 

277.0 

247.0 

1166.4 

919.4 

552 

8.84 

.1131 

33-3 

48 

278.3 

248.4 

1166.8 

918.5 

54 i 

8.67 

.1153 

34-3 

49 

279.6 

249.7 

1167.2 

917.5 

53 i 

8.50 

.1176 

35-3 

5 o 

280.9 

251.0 

1167.6 

916.6 

520 

8-34 

.1198 

36.3 

5 i 

282.1 

252.2 

1168.0 

915.7 

5 H 

8.19 

.1221 

37-3 

52 

283.3 

253.5 

1168.4 

914.9 

502 

8.04 

.1243 








































12 


QUESTIONS AND ANSWERS 




Table i —Continued 


r - ‘ 

Gauge Pressure 

Lbs. per Sq. In. 

Absolute Pressure 
Lbs. per Sq. In. 

Temp. 

Degrees F. 

Total Heat 
Above 32 0 F. 

Latent Heat 

H-h 

Heat-units 

Relative Volume 

Cubic Feet in 

1 Lb. Wt. of Steam 

Wt. of 1 Cubic Foot 

of Steam, Lbs. 

In the Water 
h 

Heat-units 

In the Steam 

H 

Heat-units 

II 4-3 

129 

346.5 

318.4 

1187.6 

869.2 

213 

3-45 

.2915 

II 5-3 

130 

347-1 

3 I 9 -I 

1187.8 

868.7 

212 

3-41 

.2936 

116.3 

131 

347-6 

3 I 9.7 

1188.0 

868.3 

210 

3-38 

.2957 

II 7-3 

132 

348.2 

320.3 

1188.2 

867. 9 

209 

3.36 

.2978 

118.3 

133 

348.8 

320.8 

1188.3 

867.5 

207 

3-33 

.3000 

II 9-3 

134 

349-4 

321.5 

1188.5 

867.0 

206 

3.31 

.3021 

120.3 

135 

35 o.o 

322.1 

1188.7 

866.6 

204 

3-29 

.3042 

121.3 

136 

350.5 

322.6 

1188.9 

866.2 

203 

3-27 

.3063 

122.3 

137 

35 i.1 

323.2 

1189.0 

865.8 

201 

3.24 

.3084 

123.3 

138 

351.8 

323.8 

1189.2 

865.4 

200 

3-22 

.3105 

124.3 

139 

352.2 

324.4 

1189.4 

865.0 

I99 

3-20 

.3126 

125.3 

140 

352.8 

325.O 

1189.5 

864.6 

197 

3.18 

•3147 

126.3 

141 

353-3 

325.5 

1189.7 

864.2 

I96 

3.16 

.3169 

127.3 

142 

353-9 

326.1 

1189.9 

863.8 

195 

3.14 

.3190 

128.3 

143 

354-4 

326.7 

1190.0 

863.4 

193 

3 -11 

.3211 

129.3 

144 

355.0 

327.2 

1190.2 

863.0 

192 

3-09 

.3232 

130.3 

145 

355.5 

327.8 

1 J90.4 

862.6 

191 

3.07 

.3253 

I 3 I -3 

146 

356.0 

328.4 

II 90-5 

862.2 

I9O 

3-05 

.3274 

133-3 

148 

357.1 

329.5 

1190.9 

861.4 

187 

3-02 

.3316 

135.3 

150 

358.2 

330.6 

1191.2 

860.6 

185 

2.98 

.3358 

140.3 

155 

360.7 

333-2 

1192.0 

858.7 

179 

2.89 

.3463 

145.3 

160 

363.3 

335-9 

1192.7 

856.9 

174 

2.So 

.3567 

150.3 

165 

365.7 

338.4 

H 93-5 

855-1 

I69 

2.72 

.3671 

155.3 

170 

368.2 

340.9 

1194.2 

853.3 

164 

2.65 

• 3775 

160.3 

175 

370.5 

343-4 

1194.9 

851.6 

l6o 

2.58 

.3879 

165.3 

180 

372.8 

345-8 

1195.7 

849.9 

156 

2.51 

.3983 

170.3 

185 

375-1 

348.1 

1196.3 

848.2 

152 

2.45 

.4087 

175.3 

190 

377-3 

350.4 

1197.0 

846.6 

148 

2-39 

.4191 

180.3 

195 

379-5 

352.7 

1197.7 

845.0 

144 

2-33 

.4296 

185.3 

200 

381.6 

354-9 

1198.3 

843-4 

141 

2.27 

.4400 

190.3 

205 

383.7 

357-1 

1199.0 

841.9 

138 

2.22 

.4503 

195.3 

210 

385-7 

359-2 

1199.6 

840.4 

135 

2.17 

.4605 

200.3 

215 

387.7 

361.3 

1200.2 

838.9 

132 

2.12 

• 4707 

205.3 

220 

389-7 

362.2 

1200.8 

838.6 

129 

2.06 

.48^,2 

245.3 

260 

404.4 

377-4 

1205.3 

827.9 

no 

1.76 

. 5686 

28^.3 

300 

417.4 

390.9 

1209.2 

818.3 

96 

1-53 

.6515 

485 3 

500 

467.4 

443-5 

1224.5 

781.0 

59 

•94 

1.062 

685.3 

700 

504.1 

482.4 

1235.7 

753-3 

42 

.68 

1.470 

985 3 

IOOO 

546.8 

528.3 

1248.7 

720.3 

30 

.48 

2.082 





























STEAM, HEAT, COMBUSTION, AND FUELS 13 

Ques. 8.—How much pressure does the atmosphere 
exert upon the surface of the earth? 

Ans.— 14.7 pounds upon each square inch of the 
earth’s surface. 

Ques. 9 .—What is understood by gauge pressure? 

Ans.—Gauge pressure is the pressure over and above 
the 14.7 pounds atmospheric pressure. 

Ques. 10.—What is absolute; pressure? 

Ans.—Absolute pressure is the total pressure above a 
perfect vacuum. It equals the sum of the gauge press«u 
and the atmospheric pressure. 

Ques. 11.—How does pressure influence the boiling 
point of water? 

Ans.—The higher the pressure, the higher must the 
temperature of the water be raised in order to cause it to 
boil. 

Ques. 12.—In what way does pressure affect the vol¬ 
ume of steam? 

Ans.—The higher the pressure, the smaller will be the 
volume of the steam generated from a given weight of 
water. 

Ques. 13 .—In what light should steam be considered 
relative to work? 

Ans.—As an agent through which heat performs the 
work. 

Ques. 14 .—What is the most important property of 
steam? 

Ans.—Its expansive force. 

Ques. 15 .—What law governs this expansion? 

Ans.—Boyle’s law of expanding gases. 


14 


QUESTIONS AND ANSWERS 


Ques. 16 .—Define Boyle’s law. 

Ans.—The volume of all elastic gases is inversely pro¬ 
portional to their pressure. 

Ques. 17 .—What is heat? 

Ans.—Heat is a form of energy which may be applied 
to or taken away from bodies. 

Ques. 18 .—Name the original source of heat, at least 
for this planet. 

Ans.—The sun. 

Ques. 19 .—How was this heat made available for 
man’s use? 

Ans.—By being stored up in oil, wood, and the coal 
formations millions of years ago, by the rays of the sun. 

Ques. 20.—What is the relation of heat to matter? 

Ans.—All matter is charged with heat in a greater or 
less degree, depending upon the nature of the matter. 

Ques. 21.—What is the specific heat of any substance? 

Ans.—The ratio of the quantity of heat required to 
raise a given weight of that substance 1 degree in temper¬ 
ature, to the quantity of heat required to raise the same 
weight of water 1 degree in temperature, the water being 
at its maximum density, 39.1 degrees. 

The following table gives the specific heat of different 
substances in which engineers are most generally inter¬ 
ested: 

Table No. 2 


Water at 39.1 degrees Fahrenheit.1.000 

Ice at 32 degrees Fahrenheit.504 

Steam at 212 degrees Fahrenheit. 480 

Mercury. 033 

Cast iron. 130 















15 




STEAM, HEAT, COMBUSTION, AND FUELS 


Table No. 2— Continued 


o* 


ed 

st 


Wrought iron 

Soft steel. 

Copper . 

Lead. 

Coal . 

Air. 

Hydrogen ... 

Oxygen . 

Nitrogen .... 


Ques. 22.— 


ft 

What is sensible heat? 


.113 

.116 

.095 

.031 

.240 

.238 

3.404 

.218 

.244 


)r 

al 

D. 

)r 

>? 


:o 


le 

?! 


it 


9 

1 

) 

) 

) 


Ans.—Heat imparted to a body, and warming it. 
Sensible heat in any substance can be measured in degrees 
of a thermometer. 

Ques. 23 .—What is latent heat? 

Ans.—Heat given to a body and not warming it; that 
is, the heat that is not shown by the thermometer. 

Ques. 24 .—Is the heat lost that thus becomes latent? 

Ans.—It is not. On the contrary, it was required to 
produce the change in the body from the solid to liquid, 
or from the liquid to the gaseous state. For instance, in 
the transformation of ice into water, 180 degrees of heat 
becomes latent, and in changing the water into steam at 
atmospheric pressure 965.7 degrees of heat become 
latent. 

Ques. 25 .—What is the first law of thermo-dyna¬ 
mics? 

Ans.—Heat and work are mutually convertible; that 
is, a certain amount of work will produce a certain 
amount of heat, and the heat thus produced will, by its 
disapoearance, if rightly applied, produce a fixed amount 
C It mechanical energy. 
















16 


QUESTIONS AND ANSWERS 


Ques. 26.—How is heat measured with relation to 
work? 

Ans.—By the thermal unit. 

Ques. 27.—What is a thermal unit? 

Ans.—It is the quantity of heat required to raise the 
temperature of one pound of pure water one degree, or 
from 39 degrees, its temperature of greatest density, to 



40 degrees. 




Ques. 28.—What is the mechanical equivalent of 
heat? 

Ans.—The mechanical equivalent of heat is the 
energy required to raise a weight of 778 pounds one foot 
high, or a weight of one pound 778 feet high; in other 
words, 778 foot pounds. This amount of energy is stored 
in one thermal unit, or heat unit. 

Ques. 29.—In how many ways is heat transmitted? 

Ans.—In two ways:—First by conduction; second, by 
radiation. 

Ques. 30.—What is conduction of heat? 

Ans.—Conduction is the transmission of heat from 
one body to another in direct contact with it. 

Ques. 31.—Are all bodies equally good conductors of 


heat? 

Ans.—No. The best conductors of heat are the 
metals, silver, copper, tin, steel, lead. The poorest 
conductors, or nonconductors, as they are termed, are | 

I 

hair, wool, straw, wood, liquids, and “dead” air, that is, i 
air not in circulation. 

Ques. 32.—What is radiation of heat? 

Ans.—Radiation is the transmission of heat from one 




STEAM, HEAT, COMBUSTION, AND FUELS 


17 


0 body to another through an intervening space between 
the bodies. 

Ques. 33.—How is the heat in the furnace or fire-box 
of a boiler transmitted to the water in the boiler? 

Ans.—By radiation and conduction through the heat- 
r ing surface of the boiler. 

0 Ques. 34.—What is combustion? 

Ans.—Combustion is the chemical union of the carbon 
* and hydrogen of the fuel with the oxygen of the air. 

Ques. 35.—What is one. of the main factors in the 
c proper combustion of fuels, especially coal? 

Ans.—A proper supply of air. 

Ques. 36.—What is the principal constituent of coal, 
^ oil, and most other fuels? 

Ans.—Free or fixed carbon. 

Ques. 37.—Are there other combustibles in fuels? 

Ans.—Yes; hydrocarbons, a chemical combination of 
carbon and hydrogen in different ratios. 

Ques. 38.—State the composition of air. 

Ans.—By volume, 21 parts oxygen and 79 parts 
nitrogen; by weight, 23 parts oxygen and 77 parts 
nitrogen. 

Ques. 39.—In what proportion do the atoms of carbon 
ie and hydrocarbons combine with the atoms of oxygen to 
form perfect combustion? 

Ans.—One atom of carbon combines with two atoms 
5 i of oxygen, expressed by the chemical symbol CO". 

Ques. 40.—In the process of combustion, which com¬ 
bustible burns first? 

Ans.—When fresh fuel is added to the fire, the hydro- 


18 


QUESTIONS AND ANSWERS 


carbons distill in the form of gas, and if the conditions 
of draught, admission of air, etc., are right, this gas will 
ignite and burn during its passage through the furnace j 
and combustion chamber; otherwise it passes out of the 
stack in the form of smoke. 

Ques. 41.—What are the common products of com¬ 
bustion? 

Ans.—First, carbonic acid, resultant from the , 
chemical union of one atom of carbon with two atoms of 
oxygen (symbol CO 2 ); second, water vapor, resultant i 
from the chemical union of two portions of hydrogen, and 
one portion of oxygen (symbol H 2 0); third, inert gases, 
like nitrogen, also unassociated oxygen, ash, and other 
products, due to the impurities contained in the coal, or 
other fuel. 

Ques. 42.—In what form does the fixed carbon appear 
during the process of combustion? 

Ans.—After the hydrocarbons have left it, the fixed 
carbon appears in the form of a glowing mass of coke, 
uniting with the oxygen to form carbonic acid, and all 
the heat stored in the carbon is liberated, provided the 
supply of air is correct; otherwise carbon monoxide 
(symbol CO) is formed, and only about one-third of the 
stored heat is liberated, the larger portion of the carbon 
passing off in the form of soot and smoke. 

Ques. 43.—How many thermal units are contained in 
one pound of carbon? 

Ans.—14,500 thermal units. 

Ques. 44.—Theoretically, how much air is required 
lor the complete combustion of one pound of coal? 


STEAM, HEAT, COMBUSTION, AND FUELS 19 

Ans.—By weight, 12 pounds; by volume, 150 cubic feet. 
Ques. 45.—Is this law carried out in practice? 

Ans.—It is not; a much larger quantity of air (20 to 
24 pounds per pound of coal) being supplied in order to 
; nsure that all the atoms of carbon may find oxygen. 

Ques. 46.—In what two ways is the air supplied to 
boiler furnaces? 

Ans.—First, by natural draught; second, by artificial 
or forced draught. 

Ques. 47.—What causes natural draught? 

Ans.—The air in the furnace and uptake becomes 
heated and consequently much lighter in weight than an 
equal column of outside air. The heated air is therefore 
continually rising and passing out of the funnel or smoke¬ 
stack, while the outside air rushes into the ash-pit and 
up through the grates to replace it. 

Ques. 48.-^How many systems of artificial or forced 
draught are there? 

Ans.—There are two principal systems: First, that 
in which the air is forced directly into the ash-pits, 
through conduits leading directly from the fan, or other 
source of the blast; second, that in which the air is forced 
directly into the fire-room or stoke-hole, which is made 
air-tight for this purpose, and from thence the air finds 
its way into the furnaces on the same principle as when 
natural draught is employed. 

Ques. 49.—Mention the two most important factors 
in the regulation of combustion. 

Ans.—First, the draught; second, the kind and 
quality of the fuel. 



20 


QUESTIONS AND ANSWERS 


Ques. 50.—What is meant by the expression “rate of 
combustion?’' 

Ans.—The rate of combustion means the number of 
pounds of fuel burned per square foot of grate surface 
per hour. 

Ques. 51.—What are the usual rates of combustion 
with natural draught? 

Ans.—For stationary boilers with shaking grates, 
from 12 to 18 pounds of coal per hour; for marine 
boilers, from 15 to 25 pounds. 

Ques. 52.—What are the rates of combustion with 
artificial or forced draught? 

Ans.—For stationary boilers, 25 to 35 pounds; for 
marine boilers, 20 to 50 pounds. 

Ques. 53.—How should the air-supply be regulated in 
order to bring about complete combustion? 

Ans.—Complete combustion can be secured only when 
the air is brought into direct contact, not only with the 
fuel, but also with the gases as they develop. If the air 
passing into the furnace above the fuel is first heated, 
much better results can be attained. 

Ques. 54.—Why is it desirable to admit air (heated if 
possible) above the fire? 

Ans.—In order to supply to the hydrocarbons the 
oxygen necessary to their complete combustion. 

Ques. 55.—What will be the result if the supply of 
oxygen above the fire is not sufficient? 

Ans.—A portion of the hydrocarbons will pass off 
unburned, and of other portions, only the hydrogen is 
burned, leaving the carbon to pass off as soot or smoke. 




STEAM, HEAT, COMBUSTION, AND FUELS 21 

Ques. 56.—State another reason why the air should be 
admitted above the fire. 

Ans.—If carbon monoxide (CO) has been formed in 
the combustion of the fixed carbon, the air above the fin 
would burn this into carbonic acid, thereby liberating t 
large additional amount of heat. 

Ques. 57.—What is indicated by the formation ol 
much smoke and soot? 

Ans.—Incomplete combustion, as smoke and soot are 
simply unoxydized particles of carbon. 

Ques. 58.—Is a high furnace temperature conducive 
to good combustion? 

Ans.—It is; because the hydrocarbons unite with the 
oxygen much more quickly, and the fixed carbon also is 
much more completely united with oxygen in a high 
temperature. 

Ques. 59.—Mention a very efficient agency for main¬ 
taining a high furnace temperature. 

Ans.—Fire-brick arches and bafflers, for the gases to 
impinge against. 

Ques. 60.—Assuming that good combustion is taking 
place in the boiler furnace, what will be the furnace tem¬ 
perature? 

Ans.—From 2,500 to 3,000 degrees Fahrenheit. 

Ques. 61.—What are the fuels most commonly used 
in boiler furnaces? 

Ans.—Coal, wood, and oil. 

Ques. 62.—What per cent of volatile matter is con¬ 
tained in most of the coals used in the marine service? 

Ans.—About 20 per cent. 



22 


QUESTIONS AND ANSWERS 


Ques. 63.—What are the advantages of fuel oil? 

Ans.—Greater evaporative power for same weight and 
bulk, ease of manipulation, perfect control of the com¬ 
bustion to suit requirements of service, and cleanliness. 

Ques. 64.—What are the principal objections to the 
use of oil as fuel for boilers? 

Ans.—First, certain dangers involved in storing and 
using it; second, limited supply. 

Ques. 65. ; —State the difference between the heating 
value of a pound of bituminous coal and a pound of wood. 

Ans.—One pound of coal will evaporate from 8 to 
9 pounds of water; one pound of wood will evaporate 
from 2/4 to 3^ pounds of water. 

Ques. 66.—What are the two principal kinds of coal 
used as fuel for boilers? 

Ans.—First, anthracite or hard coal; second, bitumin- 
ous or soft coal. 


Ques. 67.—State the composition of hard coal. 


Ans. — *Carbon.. 


91.05 

Volatile matter. 

4« 

3.45 

Moisture.,. .. 

4 4 

1.34 

Ash . 

4 4 

4.16 

100.00 

Ques. 68. — State the composition of the best soft coals. 

Ans. — f Fixed carbon.. 


75.02 

Volatile matter. 

4 4 

20.34 

Moisture . 

u 

.61 

Ash. 

«• 

3.47 

Sulphur . 

44 

.56 

100.00 


'‘Thurston. tKent. 




















STEAM, HEAT, COMBUSTION, AND FUELS 


^3 


Ques. 69.—Does this analysis apply to all bituminous 
coals? 


Ans.—No; some of the poorer kinds run as low as 40 
per cent in carbon, 32 per cent in hydrocarbons, and 12 
per cent in ash. , 

Ques. 70.— How do these impurities affect the value 
of coal as a fuel? A* 

Ans.—The mineral combination of sulphur and iron 
affects the keeping qualities of some coals. Ashes and 


mineral substances form clinkers on the grate bars by 
fusing together, thereby greatly impeding the passage of 


air through the fire. 

Table No. 3 

Analysis of Coal from Different States. 


State 

Kind of Coal 

Moist¬ 

ure 

Vola¬ 

tile 

Matter 

Fixed 

Carbon 

Ash 

Sul¬ 

phur 

Pennsylvania 

Youghiogheny 

1.03 

36.49 

59.05 

2.61 

0.81 

( < 

Connellsville 

1.26 

30.IO 

59.61 

8.23 

0.78 

West Virginia 

Quinimont 

0.76 

18.65 

79.26 

I. II 

0.23 

< < 

Fire Creek 

0.61 

22.34 

75.02 

1-47 

0.56 

E. Kentucky 

Peach Orchard 

4.60 

35-70 

53.28 

6.42 

1.08 

• i 

Pike County 

1.80 

26.80 

67.60 

3-8o 

0-97 

Alabama 

Cahaba 

1.66 

33-28 

63.04 

2.02 

0-53 

a 

Pratt Co.’s 

1.47 

32.29 

59-50 

6.73 

1.22 

Ohio 

Hocking Valley 

6.59 

35.77 

49-64 

8.00 

1-59 

11 

Muskingum “ 

3-47 

37-83 

53-30 

5-35 

2.24 

Indiana 

Block 

8.50 

31.00 

57 - 5 o 

3.00 


< i 

4 4 

2.50 

44-75 

51-25 

1.50 


W. Kentucky 

4 4 

Nolin River 

4.70 

33 - 24 

54-94 

11.70 

2-54 

Ohio County 

3-70 

30.70 

45.00 

3.16 

1.24 

Illinois 

Big Muddy 

6.40 

30.60 

54-60 

8.30 

1.50 

4 4 

Wilmington 

15.50 

32.80 

39 - 9 ° 

11.80 


# 4 

“ screenings 

14.00 

28.00 

34-20 

23.80 


44 

Duquoin 

8.90 

23-50 

60.60 

7.00 



Ques. 71.—How is coal measured? 


Ans.—Usually bv weight in pounds or tons. For 
storage purposes between 42 and 44 cubic feet per ton of 


2,240 pounds are allowed. 




























24 


QUESTIONS AND ANSWERS 


Ques. 72.—What is the heating value in thermal units 
of one pound of bituminous coal? 

Ans.—12,000 to 14,500 thermal units, depending upon 
the quality of the coal. 

Ques. 73.—What is the average composition of wood? 

Ans.—About 50 per cent of carbon, 40 per cent of 
oxygen, some hydrogen, and about 1 per cent of ash. 

Ques. 74.—What is the average heating value of 
wood expressed in thermal units? 

Ans.—From 6,000 to 8,000 thermal units per pound. 

Ques. 75.—What woods are generally used for fuel? 

Ans.—Hickory, oak, beech, pines, and firs. 

Ques. 76.—What are the principal disadvantages in 
the use of wood as a fuel for steam boilers? 

Ans.—First, a limited supply; second, great bulk in 
comparison to its heating value. 

Ques. 77.—State the composition of fuel oil. 

Ans.—Fuel oil contains about 86 per cent of carbon, 
13 per cent of hydrogen, and 1 per cent of oxygen. 

Ques. 78.—What is the heating value of fuel oil? 

Ans.—20,000 to 22,000 thermal units per pound of oil. 

Ques. 79.—What are the relative heating values of 
coal and wood? 

Ans.—One pound of coal is equal to 2/4 pounds of 
wood. 

Ques. 80.—What is the best all-around fuel, with high 
heating value, and at reasonable cost? 

Ans.—Coal. It is easily obtainable very nearly every¬ 
where; it is safe to handle, and has small bulk in propor¬ 
tion to its heating value. 







CHAPTER II 


# 

THE BOILER. 

Ques. 81.—What are the leading types of boilers in 
use at the present day in the stationary and marine 
service? 

Ans.—First, fire-tube boilers; second, water tube 
boilers. 

Ques. 82.—In what respect do they differ? 

Ans.—Fire-tube boilers have the hot gases inside the 
tubes and the water surrounding them, while in water- 
tube boilers the water is inside the tubes and the hot gases 
and flame are on the outside. 

Ques. 83.—Are boilers classified in any other way? 

Ans.—Yes; low-pressure boilers, in which 55 to 60 
pounds is the limit, and high-pressme boilers, carrying 
from 150 to 300 pounds pressure. 

Ques. 84.—What are the most common forms of fire- 
tube boilers? 

Ans.—First, the horizontal tubular boiler; second, 

« 

the vertical tubular boiler; third, the Scotch boiler; 
fourth, the flue and return tube boiler; fifth, the Western 
river boiler. 

Ques. 85.—Describe the horizontal tubular boiler. 

Ans.—It consists of a cylindrical shell, having tubes 

of from 2 to 4 inches in diameter extending from head 

to head. There is usually a dome on top, and the 

boiler is set in brickwork, having the furnace underneath. 

The heated gases pass first under the boiler, and then 

25 


26 


QUESTIONS AND ANSWERS 


return through the tubes to the breeching or uptake 
leading to the stack. 

Ques. 86.—What are the leading features of the verti 

cal tubular boiler? 

* 

Ans.—A cylindrical shell, having the fire-box or fur¬ 
nace in its lower end. The bottom ends of the tubes are 
expanded into the tube-sheet of the fire-box, and the top 
ends of the tubes are expanded into the top head of the 
boiler, and conduct the gases directly to the stack. 

Ques. 87.—Are the tubes entirely submerged in this 
class of boilers? 

Ans.—Not in all cases. Some forms of vertical boilers 
have a submerging chamber above the upper tube-sheet. 
This allows of a steam space above the top ends of the 
tubes, surrounding the smoke uptake, or smoke flue lead- 
ing to the stack. The tubes are thus entirely submerged. 
In the flush-tube boiler the steam and water space is below 
the upper tube-sheet or head of the boiler, thus leaving 
the upper portion of the tubes surrounded only by steam. 

Ques. 88.—Describe the Scotch boiler. 

Ans.—The Scotch boiler may be made either single- 
ended or double-ended. The shell is cylindrical, with 
flat heads. The diameters range from 10 to 15 feet, and 
in some cases even 20 feet, with a length of from 7 to 11 
feet. The Scotch boiler is horizontal, and is provided | 
with two or more large corrugated furnace flues, placed 
near the bottom of the boiler, and extending from the 
front head to the combustion chamber in the rear. 

Ques. 89—What is the diameter of these corrugated 
flues? 







THE BOILER 


27 


Ans.—From 3^2 to 4/4 feet, depen ng upon the size 
of the boiler. 

Ques. 90.—How are these furnace flues secured in 
:he boiler? 



Ans.—One end of the flue is riveted into the front 
head of the boiler, and the back end of the flue is rivet* d 
into the front sheet of the combustion chamber. 













































































QUESTIONS AND ANSWERS 


28 




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Ques. 92.—Describe the course of the heated gases in 
the Scotch boiler. 

Ans.—The furnaces proper, are placed within the cor¬ 
rugated flues, near the front end. The gases and smoke 
pass through the flues to the combustion chamber, and 
from thence return through the small tubes to the smoke- 
box in front, and from there out through the stack. 

Ques. 93.—How are the flat sides of the combustion 
chamber stayed? 


Fig. 2 . Standard Horizontal Boiler with Full-arch Front Setting. 


Ques. 91.-—Describe the combustion chamber of the 
Scotch boiler. 

Ans.—It is a chamber built of steel boiler plate, 
located at the rear end of the boiler, and entirely sur¬ 
rounded by water. A nest of tubes extends from the 
front sheet of the combustion chamber, above the cor¬ 
rugated furnace flue, to the front head of the shell. 





























































































rHE BOILER 





Fig. 3 . Vertical Tubular Boiler, with Full-Length Iubes. 






































































































































































































QUESTIONS AND ANSWERS 


L*! 


A ns.—By stay-bolts connecting with the shell and the 
back head. The small tubes serve as stays for the front 
sheet. 



Fig. 4 . Vertical Marine Boiler, Showing Details 

of Bracing. 



Ques. 94.—What is meant by double-ended Scotch! 
boilers' 

Ans.—Boilers having furnaces at each end. A double- 
ended Scotch boiler is in fact two single-ended boilers 
placed back to back. 



































THE BOILER 


31 


Ques. 95.—What advantage has the Scotch boiler 
over other types? 

Ans.—A very large amount of heating surface in 
proportion to its cubic contents. 

Ques. 96.—What are the disadvantages connected 
with the use of the Scotch boiler? 



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Fig. 5 . Single-Ended Scotch Marine Boiler. 


Ans.—First, defective water circulation; second, 
liability to leaky tubes; third, unequal expansion of the 
parts, thereby setting up severe strains. 

Ques. 97.—Is the Scotch boiler much used? 

4ns.—It is in almost universal use in the large ocean¬ 
going mercnanr vessels. 

































32 


QUESTIONS AND ANSWERS 


Ques. 98.—What are the distinctive features of the 
flue and return-tube boiler? 

Ans.—This form of boiler is cylindrical in shape in 
that part of the shell containing the large flues and 
small return tubes, but resembles a locomotive boiler in 



Fig. 6. Double-Ended Scotch Marine Boiler, Sectional View. 


Ques. 99.—Describe the action of the heat in this 
boiler. 

Ans.—The furnace or fire-box, resembling that of a 
locomotive, is located in the front end of the boiler, s 
From thence large flues conduct the heated gases to the 
combustion chamber in the rear, similar to that of a 
Scotch boiler, and from there the gases return through 
the small tubes to the uptake. 










































































































































































































































































34 


QUESTIONS AND ANSWERS 


Ques. 100.—Describe the Western river boiler. 

Ans.—This boiler is usually very long (25 to 30 feet) 
..n proportion to its diameter. It consists of a cylindrical 
shell having two or more flues of large diameter (12 to 
14 inches) extending its entire length. It is set in brick¬ 
work in the same manner as the horizontal tubular boiler 
is ■he gases passing underneath the shell to the rear, and 
thence returning through the large flues to the uptake 



leac mg to the stack. It is a very simple boiler, and will 
withstand high pressures and hard usage. 


Ques. 101.—Describe the locomotive boiler. 

Ans.—The locomotive boiler consists essentially of a 
rectangular fire-box and a cylindrical shell. A large 
number of tubes of small diameter (2 inches) oass 
through the shell from the fire-box to the smoke-box, a 
continuation of the barrel at the front end. 



















Fig. 9. Portable or Locomotive Fire-Box Boiler, with Water Front and Open^Bottom Fire-Box. 











































































































































































































36 


QUESTIONS AND ANSWERS 


Ques. 102.—How is the fire-box joined to the outer 
shell at the bottom? 

Ans.—By a forged ring called the mud-ring, made of 
wrought iron or steel, through which long rivets pass, 
uniting the fire-box sheet and the outer sheet. 

Ques. 103.—How are the flat sides of the fire-box 
stayed? 

Ans.—By stay-blots screwed through the outer shell, 
into and through the fire sheet, and having both ends 
riveted down cold. 

Ques. 104.—How is the flat crown-sheet of a locomo¬ 
tive boiler stayed? 



Ans.—By a system of crown-bars, made in the shape 
of double girders, the ends of which rest upon the side 
sheets of the fire-box. Crown-bolts pass up through the 
crown-sheet and crown-bars, and are secured by nuts 
resting upon saddles on top of the crown-bars. The 
heads of the bolts support the crown-sheet. 

Ques. 105.—Is the locomotive boiler an economical 
boiler for stationary purposes? 

Ans.—It is not. 

Ques. 106.—Are there any other forms of cylindrical 
shell boilers besides those already referred to? 

Ans.—Yes; the Cornish boiler, having a large central 


















THE BOILER 


37 


flue, in one end of which the furnace is located; the Lan¬ 
cashire boiler, a modification of the Cornish, containing two 
internal furnace flues, and the Continental boiler. 

Ques. 107. What is meant by Galloway tubes as 
applied to a boiler? 

Ans.—Galloway tubes are conical-shaped water tubes 
which stand in an inclined position in the large flues of 
the Lancashire boiler back of the furnaces, and serve to 
circulate the water from the space below, to the space 
above the flues. They also act as bafflers to the gases in 
their passage through the flues, and thus provide increased 
heating surface. 



Fig. 11 The Lancashire Boieer. 



Fig. 12. The Galloway 
Boiler. 


Ques. 108.—Describe the Continental boiler. 

Ans.—The Continental boiler is a modification of the 
Scotch boiler, and is used to a large extent in the marine 
service. It is provided with a Morison corrugated fur¬ 
nace, and its efficiency as a steam generator has been 
established by a long series of practical tests. 

Ques. 109.—What are the leading characteristics of 
the Bonson boiler? 

Ans.—The Bonson boiler is a combination of the 
tubular and water-tube types. The water-tube member 
is in the form of a flat arch, and serves as a roof to the 
furnace. The cylindrical shell rests uoon and is con- 























38 


QUESTIONS AND ANSWERS 


nected with front and rear steel saddles (water-chambers) 
and the water-tubes are connected with the lower portion 
of these saddles. 

Ques 110.—What route do the gases take in passing 
from the furnace of the Bonson boiler to the smoke¬ 
stack? 



Fig. 13 . Continental Boiler, with Morison Corrugated 
Furnace, for Marine or Stationary Service. 



Ans.—They pass first under the water-tubes, which 
are lined with a special tile made of fire-clay, the sides of 
the furnace being also lined with fire-brick. The gases, 
after passing into the combustion chamber, at the rear, 
ascend and return through the fire-tubes in the shell, and 
from thence into the uptake at the front. 

Ques. 111.—What are the leading characteristics of 
water-tube boilers? 





THE BOILER 


39 


Ans. In water-tube boilers the larger part of the 
heating surface consists of tubes of moderate size (1 to 4 
inches in diameter). There is always some form of 
separator, drum or reservoir into which the tubes lead. 
In this drum the steam is separated from the water. In 
some forms of water-tube boilers this shell or drum is of 
considerable size. 



Fig. 14 . The Bonson Boieer and Setting. 


Ques. 112.—Is this drum exposed directly or indi¬ 
rectly to the heat? 

Ans.—It is generally exposed indirectly, as the upper 
part is used for steam space. 

Ques. 113.—What advantage is there in having a 
large size steam and water-drum? 

Ans.—The advantage of having a good free water 
surface for the disengagement of the steam. The water 
occupies about one-third of the lower portion of the drum. 









40 


QUESTIONS AND ANSWERS 


Que?. 114.—Are the upper ends of the tubes in all 
water-tube boilers entirely filled with water? 

Ans.—Not in all cases. In some forms of water-tube 
boilers the upper ends of the tubes extend above the 
water level. 

Ques. 115.—How are these different forms of water- 
tube boilers designated? 

Ans.—First, as drowned tubes; second, as priming 
lubes. 



Fig. 15 . Steel Saddle of Bonson Boiler. 


Ques. 116.—What are some of the advantages of 
water-tube boilers? 

Ans.—They may be made light, powerful and able to 
withstand high pressures. They are quick steamers, 
that is, steam may be raised rapidly from cold water;■! 
also, the circulation of the water in them is good gen¬ 
erally. 

Ques. 117.—What are some of the disadvantages 
attending the use of water-tube boilers? j 

Ans.—They are difficult to inspect and clean. Also, J 
owing to the large number of joints, leaks are liable to 
occur. 






Fig. 16 . Babcock and Wilcox Boiler, for Land Service. 

brought up near the shell, to which they are connected 
by a cross connection. The back end headers are con¬ 
nected to a mud-drum at the bottom, and to the shell at 
the top by slightly inclined tubes. The back headers 
being lower than the front headers, the tubes are thus 
inclined from front to back. 

Ques. 119.—In what style are the tubes connected to 
the headers? 

Ans.—They are staggered. 


THE BOILER 

Ques 118.—Describe briefly the Babcock & Wilcox 
water-tube boiler. 

Ans.—There is a large horizontal cylindrical shell at 
the top for the purpose of supplying steam and water- 
space. The lower half of this shell contains water, and 
the upper half steam. The tubes are expanded into 
headers at each end. At the front end these headers are 



















































42 


QUESTIONS AND ,ANSWERS 


Ques. 120.—What is meant by staggered tubes? 

Ans.—Staggered tubes are those which are not placed 



Fig. 17. Babcock and Wilcox ‘‘Alert” Type Marine Boiler. 
FromB. & W. “Book Marine Steam,” p. 154. 


Ques. 121.—What are the facilities for cleaning these 
tubes? 

Ans.—At each end of each tube there are hand-holes 
provided. 

Ques. 122.—Describe the course of the gases for the 
Babcock & Wilcox boiler. 

















THE BOILER 


43 


Ans.—A brick bridge wall at the bacK enu ot the fur¬ 
nace, together with special tiles placed among the tubes, 
compel the gases to first pass up among the tubes until 
they come in contact with the bottom of the shell for 
about two-thirds of its length from the front end. At 
this point a hanging bridge wall and special tiles deflect 
the gases downward in their course, and they again 
circulate among the tubes, passing underneath the tiles 
and up among the tubes again. The products of com¬ 
bustion thus pass over and around the tubes three times 
on their way to the uptake. 

Ques. 123.—What portions of this boiler constitute 
the heating surface? 

Ans.—The tubes, headers, and the lower half of the 
shell. 

Ques. 124.—What course does the water take in its 
circulation in this boiler? 

Ans.—Down from the shell at the rear to the water- 
tubes, thence forward and upward through the tubes. 
In its course through the tubes it becomes partially vap¬ 
orized and of less density. It then passes up into the 
shell at the front, where the steam is disengaged. 

Ques. 125.—Is the Babcock & Wilcox boiler much 
used in the marine service? 


Ans.—Yes, it is used extensively in the British and 
United States navies, also in merchant steamers. 

Ques. 126.—Is the form of this boiler the same for 
marine as for land service? 

Ans.—It is not. The chief features in which it differs 
from the land boiler are, first, a very much larger grate 




44 


QUESTIONS AND ANSWERS 



area; second, the cylindrical shell is set transversely to 
the direction of the tubes; third, the fire-doors are located 
at what would be the rear of the land boiler; fourth, thef 
tubes are much shorter, owing to the contracted space 
allowed on ocean steamers; fifth, the brickwork is sur-T 
rounded outside by a metal casing. 


Fig. 18 . The Caldwell Boiler. 


Ques. 127.—Are there any other forms of water-tube 
boilers patterned after the Babcock & Wilcox boiler? 

Ans.—There are several, prominent among which are 
the Caldwell and the Root boilers. 

Ques. 128.—Describe the Caldwell boiler. 

Ans.—It is similar in construction to the Babcock & 
Wilcox, except that the tubes, instead of being staggered 
vertically, are placed one directly above the other, with 
specially shaped fire-brick laid across alternate spaces 
between the tubes to deflect the gases. 




























THE BOILER 


45 


lk| 

tl 

4 


Ques. 129. Describe the Root water-tube boiler. 

Ans.—It consists of a nest of 4-inch tubes expanded 
into headers which are connected at front and back with a 
set of steam and water-drums about 15 inches in diameter. 
The tubes are inclined at an angle of about 20 degrees 
vfrom the horizontal. At the rear end of each overhead 
water and steam-drum is a connection leading to the 



b( 


Fig. 19. The Root Water-Tube Boieer. 


r / steam-collecting header above, placed transversely to the 
direction of the other drums, and from this header two 
connecting pipes lead to a large steam-drum located at 


& 

?d 

th 

:s 


about the center of the boiler, and above all. 

Ques. 130.—How does the water circulate in the Root 

boiler? 

Ans.—It descends through vertical connecting pipes 
from the feed-drum at the rear to the mud-drum beneath. 












































46 


QUESTIONS AND ANSWERS 


From thence it passes into the back and lower ends of the 
tubes, and on up through the tubes, and into the over¬ 
head drums, into the upper halves of which the steam is 
disengaged. 

Ques. 131.—Describe the Cahall water-tube boiler. 

A nc —The Cahall boiler is vertical, having a nest of 



Fig. 20. The Cahall Vertical Boiler. 


water-tubes standing nearly vertical. These tubes are 
connected with a shallow water-drum at the bottom, and 
a larger and deeper water and steam-drum at the top. 
The furnace is located alongside of the mud-drum, and 
the gases traverse among the tubes in a circuitous manner 
owing to bafflers placed among the tubes. 






















































































































THE BOILER 4? 

Oues. 132.—How do the gases escape to the stack 
this boiler? 



Fig. 21. Wickes Vertical Water*Tube Boiler. 

Ans.—Extending through the center of the annular 
drum at the top is a flue through which the products of 
combustion find their way to the uptake. 


























48 


QUESTIONS AND ANSWERS 


Ques. 133.—Of what form is the Wickes boiler? 


Ans.—The Wickes boiler consists of upper and lower 
vertical drums connected by vertical tubes. The furnace 

ic pvtprnQl 



Ques. 134.—What course do the gases take in their 
passage to the stack, in the Wickes boiler? 


Ans.—A thin partition wall of fire-brick is built \ 
between two adjoining middle rows of tubes. This wall 
causes the gases first to ascend to the top, and then down- 
























































THE BOILER 


49 


wards to the chimney flue at the bottom and opposite to 
the furnace. 

Ques. 135.—Describe the Stirling boiler. 

Ans.—In the Stirling water-tube boiler there are 
three horizontal steam and water-drums at the top, and 



one water-drum at the bottom. These drums are con¬ 
nected by three divisions of inclined and curved tubes. 

Ques. 136.—How are the products of combustion led 
from the furnace to the uptake, in the Stirling boiler? 

Ans.—Bafflers of fire-brick are placed back of the two 
first divisions of tubes. The first baffler causes the gases 































































50 


QUESTIONS AND ANSWERS 


to ascend to the top of the first division of tubes; the 
second baffler deflects the gases downwards, around and 
among the tubes of the second division. The draught is 
thn upwards again, surrounding the tubes composing 
th' third division, thence to the stack. 



Ques. 137.—Describe the Thornycroft boiler. 

Ans.—The Thornycroft boiler is adapted for use on 
torpedo boats and high-speed yachts. A large horizontal ] 
steam-drum at the top is connected to a water-drum at 
the bottom by two groups of curved tubes of small 































































































THE BOILER 


51 


diameter. The grates are located on each side of the 
water-drum. There are also two smaller drums at the 
bottom, one on each side, connected to the middle drum 
by small pipes. 



Ques. 138.—How does the water circulate in this 
boiler? 

Ans.—Down from the top drum to the middle lower 
drum through special return water-tubes of large 
diameter, and from thence through the smaller tubes to 
































































52 


QUESTIONS AND ANSWERS 


the side drums. From there the water passes up through 
the curved tubes to the upper portion of the top drum, 
where the steam is disengaged. , 

Ques. 139.—Describe the Niclausse boiler. 

Ans.—The Niclausse boiler is made up of a series of 
slightly inclined tubes. These tubes are double, that is, 
one inside the other, and they are connected to the front 
header in such a manner that the colder water flows down 

j 

the inside tubes and returns to the front between the two 
tubes when heated by the action of the fire and hot gases 
on the larger outside tubes. Each vertical row of tubes 
is connected at the front end to a separate header, the j 
headers being placed side by side, and all leading into a 

A 

top drum or steam-collector. 

Ques. 140.—How is the entering feed-water at the 
front kept separate from the hot ascending currents of 
water? 

Ans.—By a diaphragm in the top drum that keeps the 
cooler water separate from the hot water and steam. 

Ques. 141.—How are the tubes connected to the ! 
headers in the Niclausse boiler? 

.Ans.—By coned surfaces on the ends of the tubes 
bearing on similar coned surfaces in the headers, and kept 
in contact by outside dogs and nuts. These joints 
appear to cause no trouble by leakage. 

Ques. 142.—Is the Niclausse boiler much used? 

Ans.—It is used to some extent in the British navy, ; 
and also in several large United States* war-ships. 

Ques. 143.—Of what type is the Normand boiler? 

Ans.—The Normand boiler is a marine water-tube 





THE BOILER 


53 


boiler of the Thornycroft type. The two outer rows of 
tubes are formed into a wall of tubes, and in the vicinity 
of the furnace the tubes are arched upwards in order to 
form a combustion chamber. Back of the furnace the 



curvature is not so great, although all of the tubes are 
curved more or less, to permit of expansion when heated. 
Ques. 144.—What course do the gases take in this 

boiler? 








































Ques. 145.—What other peculiar feature character¬ 
izes the Normand boiler? 


Ans.—Provision is made tor tne admission of air 
doove the fire. 





















































































THE BOILER 


55 


Ques. 146.—How is this accomplished? 

Ans.—By means of a small air casing at the front and 
back, and a series of small holes one inch in diameter lead¬ 
ing through the brickwork to the space above the fire. 

Ques. 147.—For what kind of service is the Normand 
boiler mainly adapted? 

Ans.—For torpedo-boat destroyers. 

Ques. 148.—What is the distinguishing feature of the 
Yarrow boiler, among boilers having water-tubes of small 
diameter? 

Ans.—The Yarrow boiler has straight tubes. It also 
has at the bottom on each side a small water-chamber or 
mud-drum with nearly flat tube-plates, into which the 
tubes are expanded. The tubes run in an inclined direc¬ 
tion from these water-drums to the steam and water- 
drum at the top. 

Ques. 149. In what manner does the water circulate 
in the Yarrow boiler? 

Ans.—Those tubes which receive the most heat con- 

t 

duct the water from the lower drums to the upper drum, 
into which the steam is delivered. Other tubes which 
are cooler carry the water from the upper drum to the 
lower drums. 

Ques. 150.—Describe the Mosher boiler. 

Ans.—The Mosher boiler has two upper steam-drums 
and two lower and smaller water-drums, the water- 
drums being directly underneath the steam-drums. These 
drums are connected by curved generator pipes of small 
diameter, the pipes entering the steam-drums above the 
water-line. 




56 


QUESTIONS AND ANSWERS 


Ques. 151.—How does the water find its way from 
the upper to the lower drums? 

Ans.—By means of two external downtake pipes 
4 inches in diameter. The boiler is cased in, the casing 
being lined with fire-brick. 

Ques. 152.—For what class of service is the Mosher 
boiler mainly adapted? 

Ans.—Torpedo boats and high-speed yachts. 



Fig. 28. The Mosher Boiler. 


Ques. 153.—Describe the construction of the Almy 
boiler. 

Ans.—It is made principally of short lengths of pipe 
screwed into return bends and into twin unions. At the 
bottom there is a larger pipe or header that surrounds 
the two sides and back of the grates, and there is a 
similar structure at the top, the two headers being con¬ 
nected by the smaller pipes. 









































THE BOILER 


57 


Ques. 154.—How is the steam separated from the 
water in the Almy boiler? 



Fig. 29. The Almy Boiler. 


Ans.—The steam and water are together discharged 
from the upper header into a separator in front of the 
boiler, and from this separator the steam is drawn, while 
























































































































































Fig. 30. The Du Tempee Boiler. 


Ans.—It is provided with a coil feed-water heater 
above the main boiler. 

m 1 

Ques. 156.—Describe in general terms the Du Temple $pe 


boiler. 


58 QUESTIONS AND ANSWERS 

the separated water and the feed-water pass down 
through circulating pipes to the lower header. 

Ques. 155.—What other peculiar feature attaches to c. 
this boiler? 

t 


























































































THE BOILER 


59 


Ans.—It is of the same general character as the 
Thornycroft type, except that the generating tubes dis¬ 
ci charge into the steam-drum below the water-line. 

Ques. 157.—How are these tubes connected to the 
drums? 



Ans.—By cones and nuts. 

Ques. 158.—Is the' Du Temple boiler used to any 
, great extent? 

Ans.—Yes; it is used extensively in the French navy, 
especially on vessels of the torpedo-boat type 
Ques. 159.—Describe Reed’s boiler. 









































60 


QUESTIONS AND ANSWERS 


Ans.—This boiler resembles the Du Temple boiler. It 
has the usual top collector drum, and two lower drums 
with curved generating pipes connecting them. 

Ques. 160.—How are the tubes attached to the 
drums? 



Fig. 32. The Seabury Boieer. 

Ans.—By screwed connections at each end, with 
nuts inside the chambers. 

Ques. 161.—How are the gases caused to traverse 
the heating surface in this boiler? 

Ans.—By means of diaphragms fitted to the tubes. 

Ques. 162.—What class of service is this boiler 
largely used in? 


















































































THE EOILER 


61 


Ans.—British torpedo-boat destroyers, and also on 
third-class cruisers. 

Ques. 163.—Describe the Seabury boiler. 

Ans.—The Seabury boiler has three lower water- 
drums, the middle drum being smaller than the two out¬ 
side drums. These drums are connected to one large 
steam and water-drum above by curved pipes of small 
diameter and the furnace is divided into two sections by 
the central nest of pipes. Above the boiler tubes and 
inside the casing there is a coil feed-water heater. 

Ques. 164.—Describe the latest type of Belleville 
boiler? 

Ans.—The Belleville boiler is a water-tube boiler, and 
| is of extensive use on large ships. It is made up of two 
distinct series of straight tubes, larger in diameter than 
those of the curved type. These tubes are placed nearly 
horizontal, each alternate horizontal row being slightly 
inclined in the opposite direction to the row above it. 
The generator proper has a water-chamber below and a 
steam-drum or chamber on top, and the zigzagged tubes 
are connected to these respective chambers. 

Ques. 165.—What kind of a furnace has this boiler? 

Ans.—A rectangular brickwork furnace inclosed in a 
steel casing, and the generating tubes are placed directly 
over the grates, the bottom row of tubes being about two 
feet above the grates. Baffle plates are secured at inter¬ 
vals among the tubes for the purpose of causing the hot 
gases to traverse the whole of the heating surface. 

Ques. 166.—How is circulation of the water secured 
in the Belleville boiler? 









QUESTIONS AND ANSWERS 


Ans.—By means of external return water-pipes, one 
on each side connecting the ends of the top drum with 
the lower water-chamber, the cooler water thus passing 



Fig. 33. Belleville Boiler with Economiser. 























































































































































































































THE BOILER 


63 


down through these pipes into the lower drum, and from 
sthence the heated water passes up through the generating 
tubes, discharging into the top drum, where the steam is 
disengaged. 

Ques. 167.—What are the usual dimensions of the 
generating tubes? 

Ans.—Four and one-half inches in diameter and seven 
feet six inches in length. The ends are connected by 
being screwed into malleable cast-iron boxes. 

Ques. 168.—How is the economizer or feed-water 
heater attached to this boiler? 

Ans.—It is placed directly above the generator, a 

7 

space called the combustion chamber being left between 
the two series of tubes. The tubes of the economizer are 
smaller, being inches in diameter. The general form 
of the economizer resembles that of the generator. 

Ques. 169.—What is the course of the feed-water in 
this boiler? 

Ans.—It enters the bottom of the economizer and is 
forced upwards to and fro through the zigzagged tubes 
to the top, and from thence it falls to the bottom of the 
hot water collector at the top, and then flows to the 
return pipes, through which it passes to the generator. 

► Ques. 170.—Mention another peculiar feature of this 

boiler. 

Ans.—An automatic feed-regulating device worked 
by a float in a chamber acting upon the feed-valve. 

Ques. 171.—Is the Belleville boiler an economical 

boiler? 

Ans.—It is; an actual evaporation of from 9.3 pounds 




64 


QUESTIONS AND ANSWERS 


to 9.9 pounds of water per pound of coal having been 
obtained under test, with the feed-water at a temperature 
of 68 degrees. 

Pipe* connected to 
upper part of element 



jpnlarqed 
view or A 


inlet. 


»■«. u . Automatic Feed Regulator for Belleville Boiler. 
















































































































CHAPTER III 


BOILER CONSTRUCTION 


Ques. 172.—What is the best material to use in the 
construction of the shell of the boiler? 

Ans.—Open-hearth steel, having a tensile strength of 
from 55,000 pounds to 60,000 pounds per square inch. 

Ques, 173.—What is meant by the expression tensile 
strength (T. S.)? 

Ans.—The expression 60,000 pounds tensile strength 
means that it would require a pull of 60,000 pounds in 






•f l ’r— 




°AraJ/f»/ Sect/on _ 


ML 


t t * • 

! ) i 




1. . -j&ouM- - 


“ I 

Aboi/tZ' 



Fig. 35. Test Piece. 


the direction of its length to break a bar of the material 1 
inch square, or 2 inches wide by /4 inch thick, or 2.67 
inches wide by inch thick. 

Ques. 174.—How are steel sheets for boiler construe- 

‘ 

, tion tested? 

Ans.—A small piece, called a test piece, is cut from 
each sheet and placed in a testing machine. 

Ques. 175.—What is the working test for steel boiler 

sheets? 

Ans.—A piece from each sheet is heated to a dark 

65 













66 


QUESTIONS AND ANSWERS 


cherry red, plunged into water at 60° temperature, and 
bent double cold under the hammer, such piece to show 
no flaw or crack after doubling. 

Ques. 176.—Of what material should the tubes of 
fire-tube boilers be made? 

Ans.—A good quality of homogeneous iron. 

Ques. 177.—What is the working test for boiler tubes? 

Ans.—They should show no flaw when expanded into 
the flue-sheet and beaded. 



Ques. 178.—What should the specifications be regard¬ 
ing rivets? 

Ans.—All rivet material should be of good charcoal 
iron, or mild steel, tough and soft. Test, a good rivet 
should bend double cold, without showing fracture. 

Ques. 179.—Of what material are the tubes of water- 
tube boilers usually made? 

Ans.—Of good charcoal iron or mild steel specially 
prepared for the purpose, and lap welded, or drawn. 









BOILER CONSTRUCTION 67 

Ques. 180.—What is the test for tubes from 3/4 to 4 
inches in diameter and No. 10 wire gauge? 

Ans.—Apiece V /2 inches in length is cut from one end 
of a tube, and this piece must stand hammering down cola 
vertically without showing a crack or split, when down 
solid. 

Ques. 181.—Of what material should stay-bolts be 
made? 

Ans.—Of iron or mild steel, especially manufactured 
for the purpose. 



Ques. 182.—What should be 'the tensile strength of 
stay-bolt material? 

Ans.—For iron, not less than 46,000 pounds; for steel, 
not less than 55,000 pounds. 

Ques. 183.—What kind of material are braces and 
stays made of? 

Ans.—The material for braces and stays should be of 
the same quality as the best stay-bolt stock. 

Ques. 184.—What is the object sought in staying the 
flat surfaces of a boiler internally? 

Ans.—The object is to strengthen those surfaces 
sufficiently to enable them to withstand the maximum 
internal working pressure to which they will be subjected. 






68 


QUESTIONS AND ANSWERS 


Ques. 185.—Does the cylindrical portion of a boiler 

need bracing? , 

Ans.—It does not, for the reason that the internal j 
pressure tends to keep it cylindrical. 

Ques. 186.—What is the maximum direct pull per 
square inch of section that may be allowed on braces and 
stay-rods? 



Ans.—For iron, 6,500 pounds; for steel, 8,000 
pounds; and this point should be kept in view when spac¬ 
ing the braces. 

Ques. 187.—What is meant by spacing braces? 

Ans.—The distance from center to center that the 
stays are from each other at the point of their connection 
to the stayed surface. 

Ques. 188.—Give an example. 

Ans.—The stays in a certain boiler are spaced 8 inches 
apart, center to center, therefore each stay supports 




































BOILER CONSTRUCTION 


69 


8 x 8=64 square inches. Assuming the working pressure 
to be 100 pounds per square inch, the sectional area of 
each stay should be 1 square inch. 



Ques 189. —Suppose the working pressure is 250 
pounds per square inch and the stays are spaced 6 inches 













































































































































































































































70 


QUESTIONS AND ANSWERS 


center to center, what should be the sectional area of each 
stay? 



Ans. The pressure to be sustained by each stay would 
he 6x6 — 9000 pounds. Assume the stays to be of 




























































































































































































































































































BOILER CONSTRUCTION 


71 


steel and unwelded, and allowing a direct pull of 7,200 
pounds per square inch, the sectional area of each stay 
should be t!§{r =: 1.25 square inches; or, if the stays are 
1.5 inches smallest diameter, and a direct pull of 8.000 
pounds per square inch of section is allowed, they may be 
spaced 7 inches, center to center. 

Ques. 190.—Of what forms are boiler stays usually 
made? 

Ans.—For low-pressure boilers, crow-foot stays; for 
high-pressure boilers, through stay-rods and gusset-stays. 



Fig. 41. Common Stay-Bolt. 


Ques. 191.—Where are stay-bolts used? 

Ans.—In fire-box boilers, and all boilers of the loco¬ 
motive type, to tie the fire-box to the external shell. 

Ques. 192.—How are stay-bolts applied? 

Ans.— A continuous thread is cut on the stay-bolt rod, 
the same thread being also tapped in the holes in the 
external plate, and the inside sheet. The steel stay-bolt 
is then screwed through the plates and allowed to project 
far enough at each end to permit of its being riveted down 
cold. 

































72 


QUESTIONS AND ANSWERS 


Ques. 193.—What is the principal cause of the break* 
ing of stay-bolts? 

Ans.—The unequal expansion of the sheets into which 
they are screwed. 

Ques. 194.—Why are stay-bolts sometimes drilled 
partly through their length? 

Ans.—In order that, if the bolt breaks, the steam or 
water may blow out through the small hole and give 
warning of the break. 

Ques. 195.—Describe the Tate flexible stay-bolt. 



Ans.—The outer head is ball shaped, and is inclosed 
within a socket formed by a sleeve that screws into the 
outer sheet and a cap that screws onto the sleeve. The 
other end of the bolt is screwed into and through the fire- 
sheet a sufficient distance to allow of riveting. 

Ques. 196.—What is meant by the efficiency of a 
riveted joint? 

Ans.—It is the per cent, of strength of the solid plate 
that is retained in the joint. 

Ques. 197.—What is the efficiency of a properly 
proportioned double riveted butt-joint? 
























BOILER CONSTRUCTION 


73 


Ans.—From 71 to 75 per cent. 

Ques. 198.—What is the efficiency of a properly pro¬ 
portioned triple riveted butt-joint with inside and outside 
welts or butt-straps? 

Ans.—From 85 to 88 per cent. 



Ques. 199.—Where is the weakest portion of the triple 
riveted butt-joint? 

Ans.—At the outer row of rivets. 


Table 4 

Table of Diameters of Rivets* 


Thickness of 
Plate 

Diameter of Rivet 

Thickness of Plate 

Diameter of Rivet 

V 4 inch 

V2 inch 

9 /ie inch 

7 /s inch 

a /ie “ 

9 /ie “ 

5 /s “ 

15 /i6 “ 

3 /s “ 

n /l6 “ 

3 U “ 

IVie “ 

7 /ie “ 

3 /4 “ 

7 / 8 “ 

IVs “ 

% “ 

13 /,« “ 

1 " 

IV4 “ 


♦Machine design—W. C. Unwin. 


Ques. 200.—What percentage of efficiency may be 
retained in a properly designed quadruple riveted butt- 
joint having both inside and outside butt-straps? 

Ans.—94 per cent. 












































QUESTIONS AND ANSWERS 


U 

Ques. 201. —Where is the weakest portion of such a 
joint? 

Ans.—At the outer row of rivets. 



Fig. 44. Double Riveted Butt-Joint. 


Ques. 202.—How may boiler heads be constructed 
which will not require to be stayed? 

Ans.—By being dished, or “bumped up.” 



Fig. 45. Triple Riveted Butt-Joint. ( 

Ques. 203. \\ hat is the depth of dish, as adopted by 

steel-plate manufacturers? 


















































BOILER CONSTRUCTION 


75 


Ans.—One eighth of the diameter of the head, when 
flanged. 

Ques. 204.—What should be the thickness of the head 
as compared to the thickness of the shell? 


> 



CD 


Fig. 46. Quadruple Riveted Butt-Joint. 


Lloyd’s rules, condensed, are as follows: 

Lloyd’s Rules—Thickness of Plate and Diameter of Rivets 


Thickness of 
Plate 

Diameter of 
Rivets 

Thickness of 
Plate 

Diameter of 
Rivets 

inch 

$4 inch 

Va inch 

7/$ inch 

7 /l6 

5/8 “ 

Hie “ 

n “ 

/ “ 

3 / “ 

/8 “ 

i “ 

9 /l0 “ 

3 / “ 

15 /ie “ 

i “ 

5/8 “ 

Hie “ 

Va “ 

% “ 

1 “ 

i “ 


Ans.—The heads should be as thick, or slightly thicker, 
than the shell plate. 























































































76 


QUESTIONS AND ANSWERS 


Ques. 205.—What method other than riveting may¬ 
be, and sometimes is employed in the formation of boiler 
seams? 

Ans.—Boiler seams may be welded if the material 
from which the plates are rolled is of the best, and.great 
care and skill are exercised. 

Ques. 206.—Mention two of the advantages possessed 
by welded seams over riveted seams? 


Table 5 

Proportions of Triple-riveted Butt Joints with Inside and 

Outside Welt 


Thickness of 
Plate 
Inches 

Diameter of 
Rivet 
Inches 

Pitch of 
Rivet 
Inches 

Pitch of 
Outer Rows 
Inches 

Efficiency 
Per Cent 

3 /s 

13 /l6 

3.25 

6.5 

84 

V 16 

13 /l6 

3.25 

6.5 

85 

V 2 

13 /l6 

3.25 

6.5 

83 

9 /l6 

Vs 

3.50 

7.0 

84 

Vs 

1 

3.50 

7.0 

86 

3 U 

l‘/,6 

3.50 

7.0 

85 

Vs 

1V 8 

3.75 

7.5 

86 

1 

174 

3.87 

7.7 

84 


Ans.—First, a good welded joint approaches more 
nearly to the full strength of the material than can 
possibly be attained by rivets, no matter how correctly 
designed the riveted joint may be; second, the welded 
joint, having a smooth surface inside the boiler, is much 
less liable to collect scale and sediment than is the riveted 
joint. 

Ques. 207.—Why should the longitudinal or side 
seams of a boiler be stronger than the girth or round¬ 
about seams? 


















BOILER CONSTRUCTION 


77 


Ans.— Because the force tending to rupture the boiler 
along the line of the longitudinal seams is proportional 
to the diameter divided by two, while the stress tending 
to pull it apart endwise is only one-half that, or propor¬ 
tional to the diameter divided by four. 


Ques. 208.—What is the formula for 
the bursting pressure of a boiler? 


Ans.— 


TS X T X E 
R 


— B, in which 


ascertaining 


T S = Tensile strength 
T = Thickness of sheet 
E = Efficiency of joint 
R = Radius (one-half the 
diameter) 

B = Bursting pressure 

Ques. 209.— How is the safe working pressure of a 
boiler ascertained? 

Ans.—First calculate the bursting pressure, then 
, divide this by the factor of safety, which usually is five, 
although in some instances a safety factor of eight is used. 

Ques. 210.—In addition to the regular bracing and 
staying, how are the heads of return tubular and Scotch 
marine boilers greatly reenforced? 

Ans.—By the tubes, which are expanded into the 
heads and beaded down on the ends. 

Ques. 211.—Are the tubes always expanded into the 
tube-sheets? 

Ans.—They are in fire-tube boilers. In some forms 
of water-tube boilers the tubes are screwed into the 
headers or chambers. 







78 


QUESTIONS AND ANSWERS 


• Ques. 212,—What type of furnace is largely used in 
internally fired boilers? 

Ans.—The Morison corrugated furnace. 

Ques. 213.—Mention three advantages gained by the 
use of corrugated furnaces. 

Ans.—First, the corrugations (if properly made) add 
great rigidity and strength to resist the crushing strain to 
which the furnaces are subjected; second, there is more 
heating surface in a corrugated than in a smooth surface; 
third, the alternate expansion and contraction of the 



Fig. 47. Section of Tube Expanded into Sheet. 

corrugated surface tends to loosen any scale that may 
form on the surface inside the boiler. 

Ques. 214.—In regard to riveted seams, which is the 
better method, to drill or to punch the rivet-holes? 

Ans.—The rivet-holes should be drilled. In good 
boiler work this method is now always followed. 

Ques. 215. —What other important point should be 
kept in view in joining the plates of a boiler? 

Ans.—To get the joint tight without caulking, or at 
least with as small an amount of caulkinsr as possible. 






BOILER CONSTRUCTION 


79 


Ques. 216.—Mention some of the injurious effects of 
excessive caulking. 

Ans.—First, it is one of the most fruitful causes of 
grooving along the edges of the seams; second, it tends 
fto raise the edge of the plate that is caulked, thereby 
causing looseness at the joint. 

Ques. 217.—What other very important point should 
be secured in the construction of the boiler? 


c Ans.—The rivet-holes in the plates should come fair 

t before the rivet is put in. 



Fig. 48. Morison Corrugated Furnace. 


Ques. 218.—If the rivet-holes do not come fair what 
12 should be done with them? 

Ans.—They should be made exactly true by the use of 
tf a rimer. 

Ques. 219.—What should not be done with the rivet- 
ik holes in case they do not come fair? 

Ans.—They should not be drifted. A drift-pin is 
jbften the primary cause of starting a crack in a sheet. 

Ques. 220.—What can be said generally concerning 
- the construction of a boiler, especially one intended for 
high pressures? 






so 


QUESTIONS AND ANSWERS 


Ans.—Only the best material should be used, and 
great care and skill should be exercised in all the detail 
of assembling it. 

By reference to Chapter I, Part 2, of Swingle’s 
“Twentieth Century Hand Book for Engineers and Elec¬ 
tricians,” the student will be enabled to obtain much 
more detailed information concerning boiler construction, 
the strength of riveted joints, bracing and staying, 
strength of material, etc., as all of these important feat- ' 
ures are dwelt upon at length and fully discussed. 




CHAPTER IV 


BOILER SETTINGS AND APPURTENANCES. 

Ques. 221.—What kind of a setting is required for 
internally fired boilers? 

Ans.—First, a good solid foundation, second, the 
boiler should be covered with non-conducting, non-com¬ 
bustible material of some sort, to prevent radiation of 
>heat, and the whole should be encased in a sheet-metal 
jacket. 



Fig. 49. Plan and Elevation of Boiler Setting, Showing Air Spaces. 


Ques. 222.—What kind of a setting is required for 
horizontal tubular and water-tube boilers? 

Ans.—Brick walls with an inner lining of fire brick. 
When the boiler is supported by lugs resting upon 
the walls, a heavy iron plate should be imbedded in the 
t brickwork, for each lug to rest upon. The walls should 
also be tied together, both endwise and transversly, by 
iron rods not less than l l A inch in diameter, extending 
clear through in both directions, the bottom rods to be 
laid in place as the walls are being built. These rods are 

to have a thread and nut on each end, and are secured 

81 


































82 


QUESTIONS AND ANSWERS 


to heavy cast or wrought iron bars called buck stays, 
placed vertically against the outside of the walls. 

Ques. 223.—How may boiler walls be greatly pro¬ 
tected from the injurious action of the heat? 

Ans.—By leaving an air-space of 2 inches between the 
fire-brick lining and the outer wall, beginning at the 
level of the grate bars and extending as high as the cen¬ 
ter of the boiler. Above this height the walls should be 
solid. 



Ques. 224.—What is the duty of bridge-walls and 
bafflers? 

Ans.—To present a hot surface for the unconsumed 
gases to impinge against, and also to divert the gases 
towards the heating surface of the boiler. 

Ques. 225.—How may a good and durable back arch 
for a horizontal tubular boiler be constructed? 

Ans.—Take flat bars of iron inch thick by 4 inches 
ii 2 width, cut them to the proper length, bend them to the 











BOILER SETTINGS AND APPURTENANCES 


83 


shape of an arch, and turn 4 inches of each end back at 
right angles. The clamp thus formed is to be filled with 
a course of side arch fire-brick, and will form a complete 
and self-sustaining arch 9 inches wide and with sufficient 
spring to cover the distance between the back wall and 
the back head of the boiler above the tubes. Enough of 
these arches should be made so that when laid side by 
side they will cover the distance from one side wall to 
the other, across the rear end of the boiler. 



Ques. 226.—What advantages do this form of back 
arch possess over the ordinary flat cover? 

Ans.—First, it can come and go with the expansion 
and contraction of the boiler; second, it always maintains 
a practically air-tight cover at this important point; 
third, in case of needed repairs to the back end of the 
boiler the sections may be easily removed, one at a time, 
and when the repairs are completed they may be reset with 
very small expense. 




































84 


QUESTIONS AND ANSWERS 


Ques. 227.—Give an easy rule for ascertaining the 
dimensions of the grates. 

Ans.—For a horizontal tubular, the length of the 
grates should equal the diameter of the boiler. The j 
width depends upon the construction of the furnace. If 
the fire-brick lining is built perpendicular, the width of 
grate will also equal the diameter of the boiler, but if 



the lining is given a batter of 3 inches, starting at the 
level of the grates, then the width of grate will be 6 
inches less. 

Ques. 228.=—What is the ordinary ratio of grate s ar- 
face to heating surface for land boilers, with natural 
draught? 

Ans.— One square foot of grate surface to every 36 
square feet of heating surface. 
























































BOILER SETTINGS AND APPURTENANCES 


85 


Ques. 229.—What ratio of grate surface to heating 
surface is usually chosen with forced draught? 

Ans.—One square foot of grate surface to 40 square 
feet of heating surface, and in some instances the ratio 
is as high as 1 to 50. 

Ques. 230.—How many different styles of grate-bars 
are in general use? 

Ans.—Four; first, the common stationary grate, 
consisting of a plain cast-iron bar tapered in cross 



PLAIN GRATE 

(.STANDARD PATTON ) 



TUPPER OR HERRING-BONE GRATE 



Fig. 53. Grate Bars. 


section and having small projections cast on the sides to 
keep the bars apart a sufficient distance; second, herring¬ 
bone grates, consisting of channel-shaped cast-iron bars 
having V-shaped openings on top to allow the air to pass 
through to the fire; third, shaking or rocking grates, 
fourth, dumping grates. 

Ques. 231.—What percentage of the total grate area 
is usually allowed for the admission of air through the 
grates? 






86 


QUESTIONS AND ANSWERS 


Ans.—From 30 to 50 per cent, depending upon the 
kind of coal used. 

Ques. 232.—What is the heating surface of a boiler? 

Ans.—All the suriaces that are in contact with and 
covered by water on one side and surrounded by flame or 
hot gases on the other side. The areas of these surfaces 
are estimated in square feet and added together. 



Fig. 54. M’Ceave’s Grates. 



Ques. 233.—Is it possible to estimate the horse-power 
of a boiler from its heating surface? 

Ans.—It is in a general way, but not accurately. 

Ques. 234.—How many square feet of heating surface 
are usually allowed per horse-power? 

Ans.—From 10 to 16 square feet, depending entirely 
upon the type of boiler. 

Ques. 235.—Give seme examples. 


















BOILER SETTINGS AND APPURTENANCES 


87 


Ans.—For water-tube boilers 10 to 12 square feet of 
heating surface; for horizontal fire-tube, 12, for vertical 
fire-tube, 12 to 15, and for locomotive boilers, 12 to 16 
square feet of heating surface per horse-power. 

Ques. 236.—Why this difference? 

Ans.—Because the heating surface is more effective 
in some types of boilers than it is in others. 

Ques. 237.—What is the rule for calculating the heat¬ 
ing surface of a horizontal tubular boiler? 

Ans.—Taking the dimensions in inches’, multiply two- 
thirds of the circumference of the shell by its length. 
Multiply the inside circumference of one of the tubes by 
its length, and this product by the number of tubes. Add 
these two products together, and to this sum add two- 
thirds of the combined areas of both tube-sheets and 
from this latter sum subtract twice the combined sec¬ 
tional areas of all the tubes. The result will be the 
heating surface in square inches, which, divided by 
144, will give the number of square feet of heating 
surface. 

Ques. 238.—What is the rule for finding the heating 
surface of vertical fire-box boilers? 

Ans.—Multiply the circumference of the fire-box by 
its height above the grate. Find the heating surface of 
the tubes by the process given in the former rule and add 
these two products together, and to this add the area of 
the lower tube sheet. From this sum deduct the sectional 
area of all the tubes. The dimensions having been taken 
in inches, the result should be divided by 144 to ascertain 
the number of square feet of heating surface, 




88 


QUESTIONS AND ANSWERS 


Ques. 239.—Why is the inside circumference of the 
tubes taken? 

Ans.—Because in fire-tube boilers this is the portion 
that is directly exposed to the heat. 

Ques. 240.—Why are the combined sectional areas of 
the tubes subtracted from the area of that portion of the 
tube-sheets that is exposed to the heat. 

Ans.—Because the effective heating surface of a 
tube-sheet is the surface remaining after the areas of the 
openings through the tubes is deducted. 

Ques. 241.—What is implied in the expression “a 
3-inch boiler tube?” 

Ans.—It means a tube 3 inches in external diameter. 

Ques. 242.—Such being the case, which .diameter 
should be considered in calculating the heating surface of 
fire-tubes? 

Ans.—Only the inside diameter, which equals the out¬ 
side diameter minus twice the thickness of the tube. 

Ques. 243.—In calculating the heating surface of the 
tubes of water-tube boilers which diameter should be 
taken? 

Ans.—The outside diameter, for the reason that the 
outside circumference is exposed to the heat. 

Ques. 244.—How is the heating surface of a water- 
tube boiler ascertained? 

Ans.—Much depends upon the style of boiler. A 
general rule and one that will apply in all cases, is to 
multiply the outside circumference of one of the tubes by 
its length, and this product by the number of tubes that 
are of a similar length and diameter. If there are vari- 


BOILER SETTINGS AND APPURTENANCES 83 

ous sections of tubes of varying lengths, the heating 
surface of each section must be ascertained separately 
and the whole added together. To this sum must be 
added the combined areas of those portions of the headers 
that are directly exposed to the heat, having first deducted 
the sectional area of the tubes. All of those portions of 
the steam and water-drums that are directly exposed to 
the heat should be estimated as heating surface also. 



The door proper has an outer and inner plate, the former being a screen plate 
with edges open for the admission of air The door is perforated with holes at 
die lower part, through which the air is drawn, and the inner plate, which is of 
cast iron, is closed at the bottom, and has holes for the discharge of air at the 
top. When the fires are alight, there is a continuous current of air flowing into 
the furnace through these plates. 


Ques. 245 .—What is the rule for ascertaining the 
heating surface of a Scotch boiler? 

Ans.—The grates being set in the large main flues, 
only one-half of each flue area is available as heating 
surface. The following rule applies: To one-half the 
combined area of the main flue add the area of one head 
between the grate and water-line, minus the total cross- 
section of the tubes, plus one-half the cross-section of 






































90 


QUESTIONS AND ANSWERS 


main flues, plus the combined inside area of the tubes, 
plus the inside area of the combustion chamber. 

Ques. 246.—Give the rule for finding the heating 
surface of a corrugated flue. 


Ans.—Multiply the average inside diameter in feet by 
the length of the flue in feet, and this product by the 



Shows another variety, the air being admitted through holes at the bottom of 
the wrought-steel door proper, a perforated inner cast-iron plate being fitted tc4 
shield the door. The wrought-steel furnace frame which carries the door also 
has an inner shield plate of cast-iron perforated with holes. 

constant 4.93. The result is square feet of heating 
surface. 

Ques. 247.—What is the duty of a safety valve? 

Ans.—To automatically relieve the boiler of alf 1 
pressure above a certain prescribed working pressure by 
allowing the surplus steam to escape into the atmosphere. 

Ques. 248.—If a boiler had no safety valve, or if the 
































































BOILER SETTINGS AND APPURTENANCES 91 

safety valve should refuse to work, and all other exit 
s from the boiler be closed, and heat continuously applied, 
\ what would be the result? 

Ans.—An explosion must of necessity occur. 

f 



Fig. 58. Pop Valve. 


Ques. 249.—How many types of safety valves are 
in use? 

Ans.—Two; the lever safety valve, and the spring- 
pop safety valve. 

Ques. 250.—Which is the best adapted to all kinds of 
service? 

Ans.—The spring-loaded pop safety valve is, for the 






































































































































































92 


QUESTIONS AND ANSWERS 




reason that any inclination o* + he boiler, such as that 
caused by the vessel’s pitching and rolling in a heavy sea, 
does not interfere with the working of a spring-pop valve, 



while on the other hand the leverage of a weighted lever 
valve decreases with any inclination of the boiler that 
























































































































































































































































BOILER SETTINGS AND APPURTENANCES 93 

would momentarily put the lever in an inclined position. 

Ques. 251. What is the United States marine rule 
for determining the area of lever safety valves for boilers? 

Ans.—“Lever safety valves to be attached to marine 
boilers shall have an area of not less than 1 square inch to 



Fig. 60 . Triplex Pop Safety Valve. 


every 2 square feet of grate surface in the boiler, and the 
seats of all such safety valves shall have an angle of 
inclination of 45 degrees to the center line of their axis.” 

Ques. 252.—What is the rule regarding spring pop 
safety valves? 






















































































































































































































































































































94 


QUESTIONS AND ANSWERS 


Ans.—Three square feet of grate surface are allowed 
to each square inch of safety-valve area. 

Ques. 253.—What other and more reliable method is , 
there of calculating safety-valve area? 

Ans.—The method by which the area of the valve is 
based upon the quantity of steam that the boiler is capable I 
of generating. ji 

Ques. 254.—Why is this method more reliable? 

Ans.—For the reason that the rate of combustion 
varies greatly under different conditions, as, for instance, t 
when forcecj draught is employed, a much higher rate of 
combustion is attained than is possible with natural 
draught. 

Ques. 255.—Do the standard rules given in answers 
251 and 252 hold good for safety-valve areas for all 
pressures? 

Ans.—No; because the rate of efflux for steam 
increases as the pressure increases. Therefore, for the 
higher pressures the total safety-valve area may be 
reduced. 

Ques. 256.—What should be the lift of a safety valve 
in order to allow the proper area of escape? 

Ans.—One-fourth of the diameter of valve. 

Ques. 257.—What is the rule for ascertaining the 
pressure at which a lever safety valve will lift when the 
weight and its distance from the fulcrum are known, as 
also the effective weight of the valve, stem, and lever? 

Ans.—Multiply the weight by its distance from the 
fulcrum. Multiply the weight of the valve and lever by 
the distance of the stem from the fulcrum, and add to the 





BOILER SETTINGS AND APPURTENANCES 


95 


former product. Divide the sum of the two products by 

the product of the area of the valve multiplied by its dis- 

# 

tance from the fulcrum. The result will be the pressure 
in pounds at which the valve will lift. 

Ques. 258.—What is the rule for finding the distance 
that the weight should be placed from the fulcrum for a 
required pressure? 

Ans.—Multiply the area of the valve by the pressure 



Fig. 61. Davis Belt Driven Feed Pump. 


at which it is desired to have it lift, and from this product 
^subtract the effective weight of the valve and lever. 
Multiply the remainder by the distance of the stem from 
the fulcrum, and divide by the weight. The quotient will 
be the required distance. 

Ques. 259.—What is the rule for ascertaining the 
weight required when all of the other factors are known? 






















































96 


QUESTIONS AND ANSWERS 



Ans.—Multiply the area of the valve by the pressure, 
and from the product deduct the effective weight of the 
valve and lever. Multiply the remainder by the distance 
of the stem from the fulcrum and divide by the distance 
of the ball or weight from the fulcrum. The quotient 
wiP be the required weight in pounds. 


Fig. 62 . Phantom View oe Marsh Independent Steam Pump. 

Ques. 260.—What can be said in general regarding 
the safety valve? 

Ans.—It is one of the most useful and important 
adjuncts of a steam boiler, and if neglected, serious v 
results are apt to follow. 

Ques. 261.—Mention the two standard methods of 
supplying the feed-water to boilers under pressure? 

Ans.—First, by the feed-Dump; second, by the 
injector. 










































BOILER SETTINGS AND APPURTENANCES 97 

Ques. 262.—What advantage has the feed-pump over 
the injector? 

Ans.—The advantage of being able to draw its supply 
of water from a heater, in which the exhaust steam is 
utilized for heating the feed-water before it enters the 

i 

boiler. Great economy in fuel is thereby effected. 

Ques. 263.—What is a duplex pump? 

Ans.—A duplex pump consists of two steam-cylinders 
and two water-cylinders, each having the necessary 
pistons and valves. The steam-valves of one side are 



Fig. 63. Worthington Duplex Boiler Feed Pump. 


operated by the other side, and vice versa. Both water 
cylinders discharge into the same main. A common 
suction main serves both water-cylinders also. 

Ques. 264.—If one side of a duplex pump becomes 
disabled from any cause, how may the other side be 
operated for the time being? 

Ans.—Loosen the nuts or tappets on the valve-stem of 
the broken side and place them far enough apart so that 
the steam-valve will be moved through only a small por¬ 
tion of its stroke, thereby admitting only steam enough to 
move the empty steam-piston and rod, and thus work the 






98 


QUESTIONS AND ANSWERS 



steam-valve of the remaining side. The packing on the 
piston-rod of the broken side should be screwed up 
tightly, so as to create as much friction as possible, there 
being no resistance in the water end. In this manner the 
pump may be operated for several days or weeks, and 
thus prevent a shut-down. 


DELIVERY 


OVERFLOW 

SUCTION 

Fig. 64. The Hancock Inspirator. 

Ques. 265.—How is the velocity of flow, or piston- j 
>peed per minute of a pump ascertained? 

Ans.—Multiply the number of strokes per minute by 
the length of stroke in feet, or fractions thereof. This 
will give the piston-speed in feet per minute. 

Ques. 26G.—How is the velocity of flow in the dis¬ 
charge-pipe ascertained? 

Ans.—Divide the square of the diameter of the water* 


STEAM 




































BOILER SETTINGS AND APPURTENANCES 


99 


cylinder in inches by the square of the diameter of the 
discharge-pipe in inches, and multiply the quotient thus 



obtained by the piston-speed in feet per minute of the 
pump- 

Ques. 267.—When the velocity in feet oer minute is 


water 

Fig. 65 The Simplex IniECTOIL 








































































































100 QUESTIONS AND ANSWERS 

known, how may the number of cubic feet discharged 
per minute be ascertained? 

Ans.—Multiply the area of the pipe in square inches 
by the velocity in feet per minute, and divide by the con¬ 
stant 144. The result will be the number of cubic feet of 
water or other fluid discharged per minute. 

Ques. 268.—How may the required size and capacity 
of feed-pump for a certain boiler be ascertained? 



Fig. 66. The Self-Acting Injector, 


Ans.—Multiply the number of square feet of grate 
surface by the number of pounds of coal it is desired to 
burn per hour per square foot of grate. This will give 
the total coal consumed per hour, which, multiplied by the 
number of pounds water evaporated per pound of coal 
will result in the total number of pounds water required 
per hour. 

Ques. 269.—How may the required size of the feed- 
pump be ascertained from the number of square feet of 
heating surface? 


























BOILER SETTINGS ANB APPURTENANCES 101 

Ans.—Allow a pump capacity of 1 cubic foot of watei 
per hour for each 15 square feet of heating surface. 

Ques. 270.—How can an injector lift and force watei 



into the boiler against the same or even higher pressure 
than the pressure of the steam supplied to the injector? 

Ans.—An injector works because the steam imparts 
sufficient velocity to the water to overcome the pressure 
in the boiler. 



























































1C2 


QUESTIONS AND ANSWERS 


Ques. 271.—What is the velocity of a jet of steam 
under 180 pounds pressure issuing from a nozzle? 

Ans.—About 3,600 feet per second. 

Ques. 272.—What is the velocity of a jet of water 
under a pressure of 180 pounds issuing from a nozzle? 



Ans.—Only 164 feet per second. 

Ques. 273.—Why does the steam have so much 
greater velocity than the water, when the pressure in both 
instances is the same? 





































































































BOILER SETTINGS AND APPURTENANCES 


103 


Ans.—Because of the latent heat that is stored in the 
steam. 

Ques. 274.—What is the purpose of the combining 
tube in an injector? 

Ans.—To bring the jet of steam and the jet of water 
into close contact in order that the steam may be con- 


a 

* p 



densed and the size of the jet reduced sufficiently to allow 
it to enter the delivery tube, which is of smaller diameter 
than the combining tube. 

Ques. 275.—What is the velocity of the combined jet 
of water and condensed steam as it leaves the combining 
tube and enters the delivery tube, assuming the steam 


















104 


QUESTIONS AND ANSWERS 


pressure in the boiler to be 180 pounds per square 
inch? 

Ans.—198 feet per second. 

Ques. 276.—What velocity is actually needed to cause 
, the jet to enter the water-space of the boiler carrying 180 
pounds pressure? 

Ans. Only 164 feet per second. The excess of 
34 feet per second imparted to the velocity of the jet 
serves to overcome the friction of the feed-pipe and 
the resistance of the main check-valve. 

Ques. 277.—In general terms, then, to what is the 
action of the injector due? 

Ans.—The action of the injector is due to the high 
velocity with which a jet of steam strikes the water enter¬ 
ing the combining tube, imparting to it its momentum 
and forming with it during condensation a continuous jet 
of smaller diameter, having sufficient velocity to over¬ 
come the pressure in the boiler. 

Ques. 278.—What is the object in fitting a boiler with 
a check-valve in the feed-pipe? 

Ans.—A check-valve is for the purpose of preventing 
the water in the boiler from backing up into the feed 
main and feed-pump. 

Ques. 2 ( 9. Where should the check-valve be located? 

Ans.—In the feed-pipe, as near to the boiler as % 
possible. 

Ques. 280. For what purpose are gauge-cocks and 
water-gauge glasses? 

Ans.— They are for the purpose of indicating the 
height of the water in the boiler while it is under pressure. 


BOILER SETTINGS AND APPURTENANCES 105 

Ques. 281 .—Describe the construction and operation 
of a glass water-gauge? 

Ans.—A water-gauge, otherwise known as a water 
column or combination, is a cast-iron or brass cylinder 
connected to the steam-space of the boiler at the top, and 
to the water-space near the bottom. The normal position 
of the safe water-level is near the middle of the water- 



Fig. 70. Low Water Alarm. Fig. 71. Combined High and 

Low Water Alarm. 

column, into one side of which are screwed brass fittings 
for the glass tube or water-glass, which is a strong tube 
of special manufacture. Each end of this tube passes 
through a stuffing box in the brass fittings. The joint 
is made steam tight by a rubber ring that fits around 
the tube and is compressed by a follower screwed onto it. 
The fittings that connect the water-column with the boiler 
are, or at least should be, equipped with automatically 
closing ball valves which will act in case the gauge-glass 
breaks. 











106 


QUESTIONS AND ANSWERS 




Ques. 282.—Where are the gauge-cocks or test-cocks 
usually connected? 

Ans.—They are usually connected to the water-column 
cylinder in such a position that the lowest one is at the 
desired water-level, one a few inches above that, and the 
third near the highest point of the heating service. These 
test-cocks should be opened several times a day in order 
to keep them clear for use in case the gauge-glass breaks. 

Ques. 283.—What is liable to happen to the water- 
column? 

Ans.—Unless the water and sediment are frequently 
blown out of it through the valve at the bottom provided 

< 

for this purpose, the tubes and connections will become 
clogged, thus preventing a free circulation of the water, 
and the true water-level in the boiler will not be indicated 
as it should be. 

Ques. 284.—What is a fusible plug? 

Ans.—A fusible plug is a 1-inch brass pipe threaded 
plug, having its center drilled out to a diameter of not 




less than >4 inch, and the hole filled with Banca tin or 




other fusible metal. 

Ques. 285.—Where should a fusible plug be attached 
to a boiler? 

Ans.—A fusible plug should always be attached to 
that portion of the boiler that is first liable to become 4 
overheated on account of the water-level becoming too 
low. 

Ques. 286.—Mention some proper locations for fusible 
plugs in various types of boilers? 

Ans.—The back head of a horizontal tubular boiler, 




BOILER SETTINGS AND APPURTENANCES 


10? 




about 3 inches above the top row of tubes, the crown- 
sheet of a horizontal fire-box boiler; the lower tube-sheet 
of a vertical boiler, or sometimes in one of the tubes a 
few inches above the tube-sheet; in the lower side of the 
upper drum of a water-tube boiler. The fusible metal 
which fills the center of the plug is of con- 
ical form in .order to prevent its being blown 
out by the pressure behind it. On the other 
hand, the melting point of this fusible metal 
is such that when the water falls below it, 
and the steam under pressure in the boiler 
comes in contact with it, the metal is melted 
and runs out, thus allowing the steam to 
escape through the hole and give the alarm. 

If the melted plug is located in the crown- 
sheet of a fire-box boiler, the escaping 

steam and water will 
quench the fire and 

thus lessen the danger 

% 

of burning the sheet. 



Fig. 72a. 


Klinger’s Water Gauge Mounting.— The usual round thin gauge glasses 
give trouble with high-pressure steam, owing to frequent fractures, whrle the 
water level is often indistinct. Klinger’s glass, designed to obviate these defects, 
gives promise of success. It consists of a thick flr.t glass, with smooth front 
and serrated back, shown in section Fig. 72. a and b, the front and back of the 
mounting, are bolted together with the glass and packing, shown by thick lines, 
between them. The serrations, when clean, cause the water to appear black, 
as in Fig. 72a. 


Ques. 287.—For what purpose is a steam-gauge 
attached to a boiler? 

Ans.—For the purpose of indicating the number of 
pounds pressure per square inch in the boiler. 






























108 


QUESTIONS AND ANSWERS 


Ques. 288 .—What type of steam-gauge is in most 
general use? 

Ans.—The Bourdon spring tube gauge. 

Ques. 289.—Describe the construction of this gauge, 
and the principle upon which it operates? 

Ans.—The Bourdon gauge consists of a thin, curved, 



FiG. 73. Auxiliary Spring Pressure Gauge. 


flattened metallic tube closed at both ends and connected 
to the steam-space of the boiler by a small pipe bent at 
some portion of its length into a curve or circle that 
becomes filled with water of condensation, and thus pre¬ 
vents the live steam from coming directly in contact with 
the tube or spring, while at the same time the full 



























































































































BOILER SETTINGS AND APPURTENANCES 


109 


pressure of steam in the boiler acts upon the tube, tending 
to straighten it. The end or ends of the spring tube 
being free to move, and connected by a suitable geared 
, rack and pinion with the pointer of the gauge, causes it 



Fig. 74. Auxiliary Spring Pressure Gauge, Sectional View. 


to move across the face of the dial, thus indicating the 
pressure of the steam in pounds per square inch on the 
inner surface of the boiler. When there is no pressure 
in the boiler the pointer should stand at 0. 

























































































































































































































































































































































110 


QUESTIONS AND ANSWERS 


Ques. 290.—How should steam-gauges be cared for? 

Ans.—They should be tested frequently by comparing 
them with a gauge that has been tested against a column 
of mercury. 

Ques. 291.—How should the steam-space of the boiler 
be connected to the main steam-pipe or header? 

Ans.—There should be a steam stop-valve placed in the 
connection between the boiler and the header. The valve 



Fig. 75. Sectional View American Pressure Gauge. 

used for this purpose is usually an angle-valve, and 
should be constructed so as to close automatically, 
especially in a battery of two or more boilers. * 

Ques. 292.—Why should this valve be self-closing iry 
case the pressure in the header is higher than the pressure 
in the boiler? 

Ans.—In order that in case of an accident to one of a 
battery of boilers the steam may be prevented from pass¬ 
ing out of the neader and into the disabled boiler. 









BOILER SETTINGS AND APPURTENANCES HI 




Ques. 293.—Describe the construction and operation 
of an automatic steam stop-valve. 

Ans.—The valve is opened and closed by means of a 
screw-stem passing out through the stuffing box, and 
fitted with a hand-wheel outside. In large-size valves this 
screw-thread is carried in a strong yoke outside the cas¬ 


ing. The pressure from the 



Fig. 76. Section of an Angle 
Stop-Valve. 


boiler is on the under side of 
the valve-disk, thus tending 
to open it. The stem or 
spindle is independent of the 
valve, and is hollow to allow 
a smaller size sliding spin¬ 
dle connected to the valve 
to pass into it. This spin¬ 
dle serves to guide and hold 
the valve steady, while at 
the same time the valve is 
free to close automatically 
any time that the pressure 
in the main exceeds the 
pressure in the boiler. 

Ques. 294.—How is the 
steam admitted to the 


whistle or the steam siren? 

Ans.—Through a special stop-valve, usually of the 
self-closing type, being worked by a spring on the valve. 


Ques. 295.—Describe the action of the steam whistle. 
Ans.—The steam whistle produces its sound by the 
vibrations of a thin stationary metallic cylinder, under 
the impact of the steam. 





































112 


QUESTIONS AND ANSWERS 


Ques. 296.—How does the steam siren produce its 
sound? 

Ans.—By means of the rotations of a small slotted 
wheel which in turning opens and closes narrow slots in 
the casing. 

Ques. 297.—How may the 
passage of water from the 
boiler into the steam-pipe be 
prevented to a large extent? 

Ans.—By means of an in¬ 
ternal pipe-extension called a 
dry pipe, that collects the 
steam from all parts of the 
steam-space through narrow 
slots on its upper side. The 
shape of these slots has a 
straining action on the steam. 

Ques. 298.—What is the 
object in equipping a boiler 
with a surface blow-off? 

Ans.—In order that it may 
catch and pass off impurities, 
such as grease, oil, and scum, 
floating on the surface of the 
water. 

Ques. 299.—Describe the construction and operation 
of the surface blow-off. 

Ans. It is connected to the boiler near the water- 
level, and carries an internal pipe-extension that ends in a 
flat pan, directly below the water-line. It should be 























































BOILER SETTINGS AND APPURTENANCES 


113 


opened quite frequently, especially when muddy water is 
being fed to the boiler. This will allow the accumulated 
scum to pass out. 



Fig. 78. Section of a Steam Siren. 


Ques. 300.—Where and how should the bottom blow- 
off be connected? 

Ans.—The bottom blow-off should be connected to 
the lowest section of the boiler, and should be fitted with 





























































































114 


QUESTIONS AND ANSWERS 


a straight-way valve, or a cock, in order that there may 
be no obstruction to the free passage of the mud and other 
sediment when the boiler is being cleaned. 

Ques. 301.—For what purpose is the hydrometer-cock, 

Ans.—In the marine serv¬ 
ice the water used in the 
boilers is more or less impreg¬ 
nated with solid matter, and it 
becomes necessary to test the 
density of the water in the 
boilers at certain intervals. 
The hydrometer-cock is for the 
purpose of drawing off a 
quantity of water from the 
boiler for testing, and is fitted 
to the water-space of the 
boiler. 

Ques. 302.—Describe the 
construction and use of the 
hydrometer. 

Ans.—It is an instrument 
having a long, slender stem, 
made of either glass or metal. 
There are two bulbs in the stem. The smaller one is 
loaded and the larger one is hollow and filled with air, 
which gives the instrument buoyancy, and keeps it in a 
vertical position. The stem is graduated in degrees, each 
degree representing the presence of one-tenth the solid 
m*rter in sea-water. 


and where is it located? 






























BOILER SETTINGS AND APPURTENANCES 115 

Ques. 303.—What prooortion of sea-water is solid 
matter? 

Ans.—One thirty-second part. 

Ques. 304.—Upon what principle are the readings 
taken from the hydrometer based? 

Ans.—Upon the principle that when any body floats 
freely, the weight of the liquid displaced is equal to the 
weight of the body floating, so that the higher the density 
of the liquid the less depth will the body sink in it. If the 
instrument sinks only to the zero mark on the scale, the 
water is fresh: if it sinks to 10 degrees, it indicates the 
presence of one-thirty-second part of solid matter, and 
if it sinks to 40 degrees, it indicates a density caused by 
the presence of four times as much solid matter as there 
is in sea-water. 

Ques. 305.—How is the water in the boiler tested 
with the hydrometer? 

Ans.—A quantity of water is drawn off through the 
hydrometer-cock, fitted for this purpose into a long pot, 
into which the instrument is inserted. 

Ques. 306.—How are boiler hydrometers graduated, 
with reference to temperature? 

Ans.—They are usually graduated to suit a tempera¬ 
ture of 200 degrees Fahrenheit, as that is about the temp¬ 
erature of the water a few seconds after being drawn off 
for testing. 

Ques. 307.—How are the expansion and contraction 
of steam-pipes provided for? 

Ans.—In the smaller sized pipes a bend can be put in 
the length of pipe that will answer the purpose, but in the 



11G 


QUESTIONS AND ANSWERS 


large pipes an expansion joint, having a stuffing box for 
the pipe to slide in and out of the adjacent pipe is fitted. 

Ques. 308.—Why is it 
necessary to place a sepa¬ 
rator in the line of pipe 
leading from the boiler to 
the engine? 

Ans.—The object of a 
separator is to provide an 
additional safeguard against 
priming, by preventing any 
water in the steam-pipe 
from entering the cylinder. 

Ques. 309.—Describe 
the ordinary separator. 

Ans.—It is a metal cyl¬ 
inder larger in diameter 
than the steam-pipe, and 
connected to the pipe near 
the engine, by flange con¬ 
nections in such a manner 
that the larger portion of 
the separator hangs in a 
vertical position below the 
pipe. It is divided from the 
top nearly to the bottom by 
a diaphragm, and the steam 
Fig. so. Expansion Joint. enters on one side, near to 

the top, and impinges against the diaphragm, passes 
underneath it, and out on the other side near the top. 






























































BOILER SETTINGS AND APPURTENANCES 


117 


INLST 



1 


Any water that reaches the separator is mostly left 
at the bottom, only the steam passing on to the engine 

0 

cylinder. A valve is provided at the bottom of the 
separator for drawing off the water. The height of the 
water in the separator is shown by a glass gauge. 

Ques. 310.—Describe the automatic steam separator. 

Ans.—In addition to the 
usual diaphragm, it is fitted 
with an automatic blow-out 
apparatus, having a float that 
is raised as the water accumu- 
lates, and which by a system 
of levers opens a valve of 
large area for drainage. The 
automatic separation also has 
a hand blow-off valve. 

Ques. 311.—What is an 
asbestos-packed cock, and 
where is it used? 

Ans.—An asbestos-packed 
cock has its top and bottom 
glands packed with asbestos, 
while the shell also has longi¬ 
tudinal grooves found in it which are packed with 
asbestos. These cocks are very suitable to use on boilers 
and steam piping where high pressures are carried, and 
at locations where cocks are more convenient than valves 
would be. 

Ques. 312.—What are funnel dampers, and for what 
purpose are they attached? 





OPAl* 
COCK * 


Fig. 81. Separator. 





























118 


QUESTIONS AND ANSWERS 


Ans.—They are hinged dampers fitted in the uptakes 
leading from the boilers to the funnel, in order that each 


'smwrur 



STEAM mr 


QlSC»A y ftct 


FACtNi HAW 

eiovarrmys 


Fig. 82. Automatic Separator. 


boiler may be shut off frem the draught when not in use, 
and they are also for use when the fires are being cleaned. 

























BOILER SETTINGS AND APPURTENANCES 


119 


These dampers should be fitted so that there are no means 
, of closing them permanently, but that if released they will 
at once assume the open position. 

Ques. 313.—What are funnel stays? 

Ans.—Wire ropes carried from the top of the funnel 
to the ship’s sides, and fitted with adjusting screws for 
the purpose of regulating the strains. 



Fig. 83. Asbestos-Packed Cock. 


Ques. 314.—What precautions should be taken with 
these stays before raising steam in the boilers? 

Ans.—The adjusting screws should be slackened in 
order to allow for the expansion in the length of the funnel 
as it becomes heated. 

Ques. 315.—What is the usual height of the funnels of 
modern vessels? 

Ans.—Ninety to 100 feet, measured *rom the furnaces. 
























































120 


QUESTIONS AND ANSWERS 























































































































































BOILER SETTINGS AND APPURTENANCES 


121 


Ques. 316.—For what purpose is the funnel cover? 
Ans. It is fitted over the top of the funnel for use 



FiC. 85. Section of Armored Cruiser, Showing 
Air Screen and Coal Bunker. 


'/A 

































































































122 


QUESTIONS AND ANSWERS 


when the ship is in harbor, or if any of the funnels are not ' 
in use, in order to prevent rain-water from entering and 
corroding the uptakes. These covers are kept a little . 
above the top of the funnel, in order to allow sufficient 
space for the escape of smoke from small fires used for^t 
airing and warming the boilers while they are lying ;i 
idle. 

Ques. 317.—How is the stoke-hold of a steamer | 
ventilated? * ,1 l 

Ans.—When natural draught only is used, screens* 
are required to keep the downward current of cool air 
separate from the upward current of warm or vitiated j 
air, otherwise the circulation will not be as good as it - 
should be. 

Ques. 318.—When forced draught is employed for they 
furnaces, how is the air supplied? 

Ans.—One of the oldest and at the same time most 
expensive methods is to admit a jet of high-pressure 
steam directly from the boilers to the base of the funnel. 
This is known as the steam blast. Another plan of! 

using the steam blast is to admit small jets of steam into i 

» 

the furnace, over the fire. 

Ques. 319.—What other principal plans for creating 
forced draught are employed? 

Ans.—First, admitting jets of compressed air into the^ 
base of the funnel, in a manner similar to the steam-jet; 
second, fitting a centrifugal fan in the uptake; third, 
blowing the air into closed ash-pits; fourth, closing the 
stoke-hold and keeping it filled with slightly compressed 
air. 




BOILER SETTINGS AND APPURTENANCES 


123 


arot 


Ques. 320.—Of the plans iust mentioned, which one is 
probably the most efficient? 

fk Ans.—Closed stoke-holds, although the third plan, 


wiz., blowing the air into closed ash-pits, is an efficient 
eor iethod, but a certain degree of danger attaches to it, on 
igiccount of the pressure in the furnaces being greater 





Fig. 86. Cross Section op Stoke-hoed, Showing Air Lock. 

ie'han that in the stoke-hold, and unless proper precautions 

t;are taken before opening the furnace doors for the pur¬ 
's*. 

j,pose of replenishing the fires, the flames may be blown 
leinto the stoke-hold and serious results follow, 
d Ques. 321.—Is this latter system of closed ash-pits 
.much in vogue? 

















































































































124 


QUESTIONS AND ANSWERS 


Ans.—It is used to a large extent in the United States 
navy, also many ships of the mercantile marine service 
The British and other navies also use it to some extent. 

Ques. 322.—How may this system of creating a forcedj 
draught be made safe, so as to guard against the flam^ 
being Mown into the stoke-hold? 



( 


} 


1 


Fig. 87. Elevation oe Stoke-hoed, Showing Air Rock. 


Ans.—By fitting a device that automatically close? 
the air-supply to the ash-pit when the furnace door ij 
opened for firing. 

Ques. 323.—What is the object of providing air-locks 
in the hold of a vessel? 
















































BOILER SETTINGS AND APPURTENANCES 


125 


Ans.—In order to provide for passage to and from 
the stoke-holds, when under pressure. 

Ques. 324.—Describe the construction and operation 
jf an air-lock? 

Ans.—An air-lock consists of a small air-tight cham¬ 
ber fitted with two hinged doors opening against the air 



In this apparatus, which is fitted in many large passenger steamers in which 
the raising of ashes on deck is objectionable, the ashes are placed in a trough 
leading to a pipe, a jet of water at a pressure of about 200 pounds per square inch 
from one of the pumps is then admitted, and scours the ashes along the pipe into 
the sea. A small valve is fitted to permit the entry of air into the pipe during 
the discharge. The apparatus is simple and efficient. 





















126 


QUESTIONS AND ANSWERS 


pressure. In passing through only one door is open a 
time which makes it nossible to enter or leave the stol 
hold without allowing much air to escape and thus redi 
the air-pressure in the stoke-hold. 

Ques. 325.—At what places aboard a ship are air-loc 
necessary? 



Fig. 89. Shaking Grates. 


Ans.—At all places where communication is h 
between the compartments under pressure and any otl 
part of the ship. 

Ques. 326.—What are the advantages in gene: 
possessed by closed stoke-holds over other systems? 
Ans.—First, a reduction in the space and weig 












































































BOILER SETTINGS AND APPURTENANCES 127 

Squired by the boilers, since, by the addition of fans and 
Greens, which are light and inexpensive, and supply the 
[l ecessary air under pressure to the furnaces, the boilers 
lay be made to develop from 20 to 25 per cent more 
: ower, than they would with natural draught; second, by 
he employment of blowing fans, a continuous supply of 
resh air in the stoke-hold is assured and the health and 
omfort of the men working there is much better provided 
ar than it would be with natural draught. 

U Ques. 327.—How are the ashes raised from the stoke- 
old to the deck, to be thrown overboard? 

Ans. —By means of the ash-tube and engine; the ash- 
^abe leading from stoke-hold to deck, and the engine 
aising the ashes in an ash-bucket, that passes through 
ae tube. Another method is by means of the ash-ejector, 
rhich is simply an inclined tube running from the stoke- 
old to above the water-line, and overboard. At the 
)wer end of this tube is a hopper, into which the ashes 
re shoveled, and at the bottom of this hopper they are 
icked up by a jet of water of high velocity, and forced 
hrough the inclined tube overboard. 









CHAPTER v 


BOILER OPERATION 

, I 

Ques. 328 . —What should be the first care of art 
engineer, or water-tender, when he goes on watch? 

Ans.—He should ascertain the exact height of the 
water in his boilers by opening the valve in each of the! 
drain-pipes of the water-columns, allowing it to blow out, 
freely for a few seconds, then closing it tight, and allowing 
the water to settle back in the glass. 

Ques. 329.—What is one of the important dut es of 
the firemen coming off watch? 

Ans.—They should have the fires clean, the ash-pits 
all cleaned out, a good supply of coal on the floor, and 

II 

everything in good condition for the oncoming force. 

Ques. 330.—What implements are needed for success¬ 
fully and quickly cleaning a fire? 

Ans.—A slice-bar, a fire-hook, a heavy iron or steel 
hoe, and a lighter hoe for cleaning the ash-pit. 

Ques. 331.—How may these tools be made, so that 
they will be light and easy to handle and at the same 
time strong and durable? 

Ans.—After the working ends have been fashioned to 
the desired shape, let each be welded to a bar of 1-inch or 
1/4-inch round iron 10 or 12 inches in length. Then 
take pieces of 1-inch or 1/4-inch iron pipe, cut to the 
length desired for the handles, and weld the shanks of the 
tools to one end of the pipe handles and to the other end 

\29 




BOILER OPERATION 


121) 


weld a ring handle or a short cross-bar to facilitate hand¬ 
ling the tools. 

Ques. 332.—When a fire shows signs of being foul 
and choked, what should be done at once? 

Ans.—Prepare to clean it by allowing one side to burn 
as low as possible, putting fresh coal on the other side 
alone. 

Ques. 333.—Describe the process of cleaning a fire. 

Ans.—When the first side has burned as low as it can, 
without danger of letting the steam-pressure drop too low, 
take the slice-bar and shove it in along the side of the fur¬ 
nace, on top of the clinker, and back to near the bridge- 
wall, then, using the door-jamb as a fulcrum, give it a 
quick, strong sweep across the fire, and the greater 
portion of the live coals will be pushed over to the other 
side. What remains of the coal-not yet consumed can be 
pulled out upon the floor with the light hoe and shoveled 
to one side, to be thrown back into the furnace after the 
clinker is removed. Having thus disposed of the live 
coal, take the slice-bar and shove it in on top of the 
grates, under the clinker, loosening and breaking it up, 
after which take the heavy hoe and pull it all out upon 
the floor, where the intense heat contained in the clinker 
should be quenched by a helper, with a pail of water, or 
water discharged from a small rubber hose. 

Ques. 334.—Having gotten one side of the fire cleaned, 

what is the next move? 

Ans.—Close the door for that side, and with the slice 
bar in the other side, push all the live coal over to the side 
just cleaned, where it should be leveled off, and fresh coal 


130 


QUESTIONS AND ANSWERS 


added. After this has become ignited treat the other 
side in the same manner. 

Ques. 335.—Can a definite code of rules for hand firing, 
be laid down, that will suit all conditions? 

Ans.—No; owing to the fact that there are so many 
different varieties of coal, some of which need very little 
stirring or slicing, while others, that have a tendency to 
coke and form a crust on top of the fire, need to be sliced 
quite often. 

Ques. 336.—Mention a few general maxims that are 
applicable to all boiler-rooms. 

Ans.—First, keep a clean fire; second, see that every 
square inch of grate surface is covered with a good live 
fire; third, keep as level a fire as possible; fourth, when 
cleaning the fire, be sure to clear all the clinkers and dead 
ashes away from the back end of the grates at the bridge- 
wall. 

Ques. 337.—Why should the face of the bridge-wall, 
especially, be kept clean and free from ashes and clinker? 

Ans.—For the reason that this is one of the best 
points in the furnace for securing good combustion, 
provided that the bridge-wall is kept clean from the grates 
up, and by keeping the back ends of the grates clean, the 
air is allowed a free passage through them and is per¬ 
mitted to come directly in contact with the hot fire-brick, 
and thus one of the greatest aids to good combustion is 
utilized. 

Ques. 338.—In firing bituminous coal, what is a good 
olan to pursue in regard to the fire-doors, with some 
finds of boilers? 


BOILER OPERATION J31 

Ans. — They should be left slightly r*pen for a few 
seconds, immediately after throwing in a fresh fire. 

Ques. 339.—Give the reason for doing this. 

Ans.—Bituminous coal contains a large percentage of 
volatile (light or gaseous) matter, which flashes into 
flame the instant it comes in contact with the live fire in 
the furnace, and if a sufficient supply of oxygen is not 
present just at this particular time, the combustion will 
be imperfect, and the result will be the formation of 
carbon monoxide, or carbonic oxide gas, and the loss of 
about two-thirds of the heat units contained in the coal. 

Ques. 340.—How may this great loss of heat be 
guarded against, in a great measure? 

Ans.—By admitting a sufficient volume of air, either 
through the fire-doors, directly after putting in a fresh 
fire, or what is still better, providing air-ducts through 
the bridge-wall, or side walls, which will bring the air 
in above the fire. 

Ques. 341.—What quantity of air is required for the 
complete combustion of 1 pound of coal? 

Ans.—By weight, 12 pounds; by volume, about 150 
cubic feet. 

Ques. 342.—Is there any advantage gained by heating 
this air before admitting it to the furnace? 

Ans.—There is a great advantage, provided the 
heat used for this purpose would otherwise be wasted. 
Great economy in fuel, and much better combustion, 
result from supplying heated air to the furnaces. 

Ques. 343.—Describe the Howden draught system, as 
used in the marine service. 




132 


QUESTIONS AND ANSWERS 


Ans.—There is a nest of tubes in the uptake that is 

I 

enveloped by the hot gases on their way to the stack. j 
*The air is caused to pass through these tubes by a . 





Fig. 90. Arrangement op the Howden Draught System. 


blower-fan, and as a consequence is heated to a high 
degree before passing into the ash-pit. Some of this hot 
air is also directed into the furnace above the fire, thus 
securing a good combustion of the fuel. 






































































































BOILER OPERATION 


133 


Ques. 344.—What precautions should be taken regard¬ 
ing cleanliness of the tubes? 


Ans.—The tubes of all boilers should ce kept clean, 
<s nd free from soot, and especially does this apply to fire- 



tube boilers, for the reason that, when these tubes become 
clogged with soot, the efficiency of the draught is 
destroyed and the steaming capacity of the boiler is 
greatly reduced, because soot not only stops the draught 
but it is also a non-conductor of heat. 







































































































































134 


QUESTIONS AND ANSWERS 


Ques. 345.—What methods are ordinarily employed 
for cleaning the soot and dust from tubes? 

Ans.—First, the steam jet, if properly made and 
connected by steam hose so as to get dry steam of high 
pressure, will do very effective work; second, a scraper 
having steel blades expanded by springs so as to fit the 
inside of the tubes snugly, should be pushed through each 
tube once or twice during each twenty-four hours of 
service. This will cut the soot loose from the inside sur¬ 
face of the tubes, and greatly facilitate blowing it out 
with the steam jet. For the tubes of water-tube boilers 



Fig. 92. Scraper for Cleaning Fire Tubes. 


the steam jet may be employed to advantage in cleaning 
the outside surfaces, and a rotary scraper driven by a 
small steam turbine is used for cleaning the scale forma¬ 
tion from the inside. 

Ques. 346.—How often should a boiler be washed out 
and cleaned inside? 

Ans.—If the feed-water is impregnated to a consider¬ 
able extent with scale-forming matter, the boiler should 
be washed out every two weeks, and if the water is very 
bad, the time should be shortened to one week. 

Ques. 347.—How should a boiler be prepared for 
washing out? 


BOILER OPERATION 


135 


Ans.—The fire should be allowed to burn as low as 
possible, and then be all pulled out of the furnace, the 
fire-doors left slightly ajar, and the dampers left wide 
open in order that the boiler may gradually cool. 

Ques. 348.—Should a boiler be blown out, that is, 
emptied of water, while there is any steam-pressure in it? 

Ans.—It should not. 

Ques. 349.—Why not? 

Ans.—For the reason that the sudden change of 
temperature from hot to cold has an injurious effect on 
the seams and braces. It is as bad a practice to cool a 
boiler down too suddenly as it is to fire it up too quickly. 



Fig. 93. Turbine Cleaner for Water Tubes. 


Ques. 350.—What effect does the too sudden contrac¬ 
tion or expansion of the boiler-plates have upon the 
riveted seams? 

Ans.—Leaks are created, and very often small cracks 
radiating from the rivet-holes are started, and these 
becoming larger with each change of temperature, will 
finally destroy the strength of the seam and serious 
results will follow. 

Ques. 351.—Suppose that all of the fire has been 
pulled from the furnace and that the boiler has stood 
until the steam-gauge indicates 20 pounds pressure, 








136 


QUESTIONS AND ANSWERS 


would it then be safe to blow all of the water out of the 
boiler? 

Ans.—It would not, for the reason that the tempera¬ 
ture of steam at 20 pounds pressure is 260 degrees 
Fahrenheit, and it may be assumed that the temperature 
of the metal of the boiler is at or near this temperature 
also. Assuming the temperature of the atmosphere in 
the boiler-room to be 60 degrees Fahrenheit there will be a 
range of 260 degrees — 60 degrees = 200 degrees Fahren¬ 
heit temperature for the boiler to pass through within a 
short time, which will certainly have a bad effect, and 
besides this, the boiler shell will be so hot that the loose 
mud and sediment left after the water has run out is 
liable to become baked upon the bottom sheets, making 
it much harder to remove. 

Ques. 852 .—Under what conditions is it best to empty 
a boiler of water preparatory to washing it out? 

Ans.—After the boiler has become comparatively cool 
and there is no pressure indicated by the steam-gauge, 
the blow-off cock may be opened and the water allowed 
to run out. The gauge-cocks and drip-valve to the 
water-column should be left open to allow the air to enter 
and displace the water, otherwise there will be a partial 
vacuum formed in the boiler, and the water will not run 
out freely. 

Ques. 353.—Mention some of the important duties of 
the boiler-washer. 

Ans.—After the water has all run out and the boiler 
has cooled sufficiently to permit it, he should go inside 
(provided there is a man-hole) and after having thoroughly 



BOILER OPERATION 


137 


U( 


tli 

cleaned the inside of the boiler, he should closely examine 
all of the braces and stays, and if any are found loose or 
ra broken, they should be repaired at once, before the boiler 
is put in service again. The soundness of braces, rivets, 
etc., can be ascertained by tapping them with a light 
hammer. 

Ques. 354.—What should be done with the tubes of 
! hire-tube boilers when they become coated with scale on 
;n their outside surfaces? 

Ans.—The boiler should be taken out of service, laid 
up temporarily, and the tubes taken out, cleaned, and 
Jse those that are not corroded or pitted too badly may be 
-made almost as good as new by cutting off 8 or 10 inches 
] sof the ends and welding pieces of new tubing on, to bring 
the tubes back to their original length, after which they 
1}) may be put back in the boiler and be good for a long term 
!of service. While the tubes are out of the boiler for re¬ 
pairs the boiler-washer will have a good opportunity to get 
^inside and clean and inspect every portion of the inside. 
Ques. 355.—What precautions should be taken when 
connecting a recently fired-up boiler with the steam main 
er 1 or header? 

af Ans.—First, the steam in the boiler to be connected 
should be raised to the same pressure as that in the main, 
then the dampers should be closed and the steam stop- 
-valve should be opened slightly, just enough to permit a 
.small jet of steam to pass through, which can be heard 
by placing the ear near the body of the valve. This jet 
of steam may be passing from the main into the newly 
connected boiler, or vice versa. Whichever way it is 










Fig. 94 


Square Open Heater. 





































BOILER OPERATION 


129 


going, the valve ought not to be opened any farther until 
the flow of steam stops. This will indicate that the pres¬ 
sure has been equalized be¬ 
tween the boiler and the main, 
and it will then be found that 
the valve will move much 
easier, and it may be gradually 
opened until it is wide open. 

Ques. 356.—Should cold 
feed-water ever be pumped 
into a boiler that is under 
steam? 

Ans.—It should not, if it is 
possible to prevent it. 

Ques. 357.—How may the 
feed-water be heated econo- 
Jmically? 

Ans.—By passing it 
through a feed-heater in which 
ihe heating agent employed is 

v he exhaust steam from the fig. 95. Interior View oe 
. Open Heater. 

engines. 

X Ques. 358.—How should the feed-water be supplied 
to a hoiler while the boiler is being fired? 
t Ans.—It should be supplied just as fast as it is evap¬ 
orated. The firing can then be even and regular. 

Ques. 359.—If the supply of feed-water should sud¬ 
denly be cut off owing to breakage of the pump or some 
Dther cause, and no other source of supply was available, 
what should be done? 



iff 


in 


IK 

if 1 

IS 

iiiiniiiiiiiiiiiiiiii»iiiiiiiiiiiiiiiii» i iii 
iiiniiiiiiiiiiiiiiiiiii 111111111111 iiiiiiiiiiiiii 
*11 














































140 


QUESTIONS AND ANSWERS 


A 


k 


si. 


Ans.—The dampers should be closed immediately, and 2 
all of the draught stopped. The fires should be deadened 0 
by shoveling wet or damp ashes in on top of them, or if ' 
ashes can not readily be procured, bank the fires over witli 

green coal broken into fine 
bits. This, with the draught 
all shut off, will keep the fires 
dead, and if repairs to the 
feed-supply can not be madep 
within a short time, the firesflx 
should be pulled, that is, if« 
they have become deadened 
sufficiently. 

Ques. 360.—Should t h ejk 
fires be pulled while they are 
burning lively? 

Ans.—No; because the 
stirring will only serve to 
increase the heat, and the dan-, a 
ger will be aggravated. 

Ques. 361.—What is the 
primary object of making 
evaporation tests of boilers? 

Ans.—To ascertain how 
many pounds of water perL 
tfound of coal the boiler is evaporating. ^ 





Fig. 96 . Baragwanath Steam 
Jacket Feed Water Heater. 


Ques. 362.—What other important details relating 
to the operation of the boilers may be ascertained through 
v Well-conducted evaporation test? 

Ans.—First, the efficiency of the boiler and furnace as 

























































































BOILER OPERATION 


141 


an apparatus for the consumption of fuel and the evap¬ 
oration of water; second, the relative value of different 
varieties of coal, and 
other fuels, as heat- 
producers; third, 
whether the boilers, as 
they are operated un¬ 
der ordinary every¬ 
day conditions, are 
being operated as 
economically as they 
should be; fourth, in 
case the boilers, owing 
to an increased de¬ 
mand for steam, fail 
to supply a sufficient 
quantity, whether or 
not additional boilers 
are needed, or whether 
the trouble could be 
overcome by a change 
of conditions in the op¬ 
eration of the boilers. 

Ques. 3G3.—What 
% are the principal data 
to be noted down dur¬ 
ing the progress of an 
evaporation test? 

Ans.—First, time—the number of hours that the test 
iS is conducted; second, the kind of coal burned; third. 



Fig 97 Closed Feed Water Heater. 


























































































































142 


QUESTIONS AND ANSWERS 


weight of coal consumed; fourth, weight of water evap 
orated during the test; fifth, weight of dry ash returned 
sixth, moisture in the coah per cent, seventh, dry coa; 
corrected for moisture: eighth, weight of combustible! 
ninth, moisture in the steam, per cent; tenth, wate 
corrected for moisture in the steam; eleventh, average 
temperature of the feed-water; twelfth, average tempera 
ture of the escaping gases; thirteenth, square feet o 
grate surface; fourteenth, square feet of heating sur 
face; fifteenth, ratio of grate surface to heating surface 

Ques, 364.—How may the weight of the coal consume'! 
during the test be ascertained? 

Ans.—By having a small platform scales fitted wit! 
a wooden platform large enough to accommodate a wheel 
barrow, or, in lieu of a barrow, a box large enough t 
contain two or three hundred pounds of coal. Ead 
wheel-barrow load, or boxful of coal that goes to th 
boiler undei test can then be weighed and the figures b 
placed upon a tally-sheet and added together at the clos 
of the test, thus giving the total weight of coal consume^ 
during the test. If, at the close of the test, there is an; 
of the weighed coal left on the floor, it should be weighe 
back and deducted from the total weight. 

Ques. 365.—How may the weight of water evaporate 
during the test be ascertained? 

Ans.—By having a hot-water meter fitted in the branc 
feed-pipe leading to the boiler under test, or if this is no 
to be had, a substitute equally as accurate can be mad 
by placing two small water-tanks, each having a capacit 
of 8 or IQ cubic feet, in the vicinity of the feed-pump 









BOILER OPERATION 


143 


These tanks can be made of light tank-iron, and each 
hould be fitted with a nipple and valve, near the bottom, 
or connection with the suction side of the feed-pump. 
The tops of the tanks may be left open. A pipe leading 
rom the main water-supply, with a branch to each tank, 
5 also needed for filling them. If an open feed-water 
eater is used, and it is possible to place the tanks low 
nough to allow a portion of the hot water from the 


SUP piy 



To Feedpump 


Fig. 98. 


eater to be led into them by gravity, it will be desirable 
p do so. If this can not be done, some other provision 
tiould be made for at least partially warming the water 
efore it goes to the boiler. The exact capacity of each 
he of these two tanks, either in cubic feet or in pounds 
f water, should be ascertained, and then all of the feed¬ 
water that is supplied to the boiler during the test is to be 
rst passed through the tanks, which should be numbered 
































144 


QUESTIONS AND ANSWERS 


one and two respectively, in order to prevent confusion 
keeping a record of the number of tankfuls of water us 
during the test. Two tanks should be provided, in ord 
that while the feed-pump is drawing the water from or 
the other one may be filled. The feed-pump that is us 
to supply the boiler under test should have no connecti* 
whatever with the main feed-supply. By keeping tab 
the number of tankfuls of water used during the test, a 

TABLE 6 


WEIGHT OF WATER AT VARIOUS TEMPERATURES 


Temper¬ 

ature 

Weight per 
Cubic Foot 

Temper¬ 

ature 

Weight per 
Cubic Foot 

Temper¬ 

ature 

Weight p 
Cubic Fc 

32° F. 

62.42 lbs. 

132 0 F. 

61.52 lbs. 

230° F. 

59*37 1 

42 ° 

62.42 

142 0 

61.34 

240° 

59.10 

52° 

62.40 

152 ° 

61.14 

2 50° 

58.85 

62° 

62.36 

162° 

60.94 

260° 

58.52 

72° 

62.30 

172° 

60.73 

270° 

58.21 

82° 

62.21 

182° 

60.50 

300° 

57-26 

Q2° 

62.II 

IQ2° 

60.27 

330° 

56.24 

102 ° 

62.00 

202 ° 

60.02 

360° 

55.16 

112 ° 

61.86 

212 ° 

59.76 

390° 

54-03 

122 ° 

6 l. 70 

220 ° 

59.64 

420° 

52.86 


multiplying this by the capacity of each tank, the to 
weight of water evaporated is ascertained. 

Ques. 3GG.—How is the weight of dry ash ascertain* 

Ans.—No water should be allowed to come in cont; 
with the ashes during the test, or if it is absolutely nec< 
sary to use water, it should be used as sparingly 
possible, and as the ashes are pulled from the furnace 
ash-pit, they should be thrown to one side, and allowed 
become dry, after which the weight can be ascertained 
means of the scales that was used for weighing the co 





















BOILER OPERATION 


145 


Ques. 367.—How is the amount of moisture in the 
( coal ascertained? 

Ans.—This can generally be obtained from the reports 
1 of the geologist of the state in which the coal was mined. 

Ques. 368.—How is the weight of dry coal corrected 
for moisture ascertained? 

Ans.—Deduct the percentage of moisture in the coal 
from the total weight of coal consumed. 

Ques. 369.—How is the weight of combustible ascer¬ 
tained? 

Ans.—Deduct the weight of dry ash returned from the 
weight of dry coal corrected for moisture. 

Ques. 370.—How is the percentage of moisture in the 
steam determined? 

Ans.—By means of an instrument called a calorimeter, 
or if such an instrument is not at hand, the condition of 
the steam as regards its dryness may be approximately 
estimated by observing its appearance as it issues from a 
pet-cock, or other small opening into the atmosphere. 
-Dry, or nearly dry steam, containing about 1 per cent of 
rnoisture, will be transparent close to the orifice through 
which it issues, and if it is of a grayish white color it may 
be estimated to contain not over 2 per cent of moisture. 
r Ques. 371.—How is water corrected for moisture in 
efhe steam arrived at? 

i Ans.—Deduct the percentage of moisture in the steam 
crom the total weight of water evaporated during the 
:est. 

Ques. 372.—How is the average temperature of the 
ieed-water obtained? 








146 


QUESTIONS AND ANSWERS 


im 




Ans.—-By means of a hot-water thermometer connect' 
to the feed-pipe near to the check-valve, but between 
and the feed-pump. If the thermometer is not attach 
to the feed-pipe, the temperature of 
the water in each tank should be 
taken and noted down, during the time 
that the feed-pump is drawing from it. 

From these notations, made at regular 
intervals during the progress of the 
test, the average temperature of the 
feed-water is easily calculated. 

Ques. 373.—How is the average 
temperature of the escaping gases 
determined? 

Ans.—By readings taken at regular 
intervals from a thermometer con¬ 
nected in the uptake. 

Ques. 374.—What should be done 
with the boiler and furnace before be¬ 
ginning an evaporative test? 

Ans.—The boiler should be thor¬ 
oughly cleaned, both inside and out¬ 
side, and especially the heating sur¬ 
face, by scraping and blowing the soot 
out of the tubes, if it be a return-tu¬ 
bular boiler, and blowing the soot and 
ashes from between the tubes if it is a 
water-tube boiler. All dust, soot, and 
ashes should be removed from the out¬ 
side of the shell, and also from the 


Fig. 99. Hot Wat 
Thermometer. 
































BOILER OPERATION 


14 ? 

combustion chamber and smoke connections. The grate- 
bars and sides of the furnace should be cleared of all 
clinker, and all air-leaks made as tight as possible. 

Ques. 375.—What should be done with the water- 
connections? 

Ans.—The boiler and all of its water-connections 
^should be perfectly free from leaks, especially the blow- 
off valve or cock. If any doubt exists as to the latter, it 
should be plugged, or a blind flange put on it. 

Ques. 376.—Why is it required that especial care be 
exercised regarding the water-connections? 

Ans.—For the reason that the test is made for the pur¬ 
pose of ascertaining the exact quantity of water that the 
toiler will evaporate with a given weight and kind of coal, 
ind if any of the water fed to the boiler during the test is 
allowed to leak away, or if any water, other than that 
which has been measured by passing it through the tanks, 
is allowed to get into the boiler during the test, the results 
will be misleading and unreliable. 

Ques. 377.—Before starting the test, what other details 
regarding the boiler should be attended to carefully? 

Ans.—The boiler should be thoroughly heated, by 
having been run for several hours at the ordinary rate. 
The fire should then be cleaned and put in good condition 
■to receive the fresh coal that has been weighed for the test. 

Ques. 378.—What should be done regarding the 

water-level? 

Ans.—At the time of beginning the test, the water- 
level in the boiler should be at or near the height ordi¬ 
narily carried, and its position should be marked by t^ing 








148 


QUESTIONS AND ANSWERS 


a cord around one of the guard-rods of the gauge-glasj 
and, to prevent any possibility of error, the height of th 
water in the glass should be measured in inches, and 
memorandum made of it. 

Ques. 379.—What data regarding the steam-pressur 
should be recorded? 

Ans.—The steam-pressure as indicated by the gaug 
should be noted at the time of starting the test, and als 
at regular intervals during the progress of the test, i 
order that the average pressure may be obtained. 

Ques. 380.—When should the test begin? 

Ans.—When all of the conditions just described hav 
been complied with and the first lot of weighed coal ha 
been fed to the furnace and the feed-pump is receivin 
water from one of the measuring tanks, the time shoul 
be noted and recorded as the starting time. 

Ques. 381.—What length of time should an evapora 
tion-test be conducted? 

Ans.—Ten hours, if it is possible to continue it tha 
long. 

Ques. 382.—What conditions regarding the steam 
pressure, condition of the fire and the water-level shoul 
prevail at the close of the test? 

Ans.—They should be as nearly as possible the sam 
at the close as they were at the beginning. The water 
level should be the same and the quantity and the conditio 
of the fire, also the steam pressure. 

Ques. 383.—How may this be accomplished? 

Ans.—Only by very careful work toward the close c 
the test. 







BOILER OPERATION 


149 


Ques. 384.—If any of the weighed coal is left on the 
loor at the close of the test, what should be done with it? 

Ans.—It should be weighed back and its weight 
leducted from the total weight. 

Ques. 385.—If a portion of water is left in the last 
ank tallied, what disposition should be made of it? 

Ans.—It should be measured and deducted from the 
cotal. 

i* Ques. 386.—In making a test of the efficiency of the 
ioiler, what is one of the most essential conditions to be 
aken into consideration? 

< Ans.—The boiler should be operated at its fullest 
capacity, from the beginning to the end of the test, and 
arrangements should be made to dispose of the steam as 
cast as it is generated. 

Ques. 387.—How may this be done? 

Ans.—If the boiler is in a battery and connected to a 
ommon header, the other boilers can be fired lighter dur* 
ing the test; but if there is but the one boiler in use, a 
/aste-steam pipe should be temporarily connected, 
through which the surplus steam, if there is any, can be 
discharged into the open air, through a valve regulated 
s required. 

Ques. 388.—If the boiler under test is fed by an 
•ejector instead of a pump during the test, from whence 
rhould the steam-supply for the injector be taken? 

Ans.—The steam for the injector should be taken 
irectly from the boiler under test, through a weil- 
rotected pipe. The steam for the pump, if one is used, 
hould also be taken from the same source. 






150 


QUESTIONS AND ANSWERS 


Ques. 389.—How should the temperature of the feed- 
water be taken when an injector is used? 

Ans.—It should be taken from the measuring tanks, 
or at least from the suction side of the injector. 

Ques. 390.—Why? 

Ans.—Because the water in passing through th* 
injector receives a large quantity of heat imparted to i 
by live steam directly from the boiler, and the tempera 
ture of the water after it leaves the injector would not b< 
a true factor for use in calculating the results of th< 
test. 

Ques. 391.—For obtaining reliable and economica 
results in an evaporation-test, what conditions ar 
essential regarding the draught? 

Ans.—There should be a good, strong draught, which 
can be regulated by a damper, as desired. There shoul 
also be a draught-gauge connected to the uptake, for th 
purpose of measuring the draught. 

Ques. 392.—Why is it necessary to measure th 
draught? 

Ans.—The principal reason for measuring the draugh, 
is that in making comparative tests of the heating valu 
of different varieties of coal, the conditions should be th 
same as near as possible in all of the tests made, an 
especially should this be the case with the draught 
Therefore, by using a draught-gauge and measuring th 
draught during each test, there will be no uncertaint 
regarding this very important element. 

Ques. 393.—Describe the construction and operatio 

cf a draught-gauge. 






BOILER OPERATION 


151 


Ans. —The usual form of dr?nght-gauge is a glass 
:ube bent in the shape of the letter U. One leg is con- 
lected to the uptake by a small rubber hose, while the 
)ther leg is open to the atmosphere. 

A scale marked in tenths of an inch is fitted between 
^;he two legs of the gauge. The 
glass tube is partly filled with water, 

.vhich will, when there is no draught, 

,;tand at the same height in both 
.egs, provided the instrument stands 
perpendicular, which is its normal 
position. When connected to the 
uptake, the suction caused by the 
iraught will cause the water in the 
,eg to which the hose is attached to 
]*ise, while the level of the water in 
,;he leg that is open to the atmos¬ 
phere will be equally depressed, and 
:he extent of the variation in frac- 
:ions of an inch is the measure of 
he draught. Thus the draught is 
referred to as being .5 .7 or .75 inch. 

Ques. 394.—What is the least 
draught that should be used, in or- 
^er to obtain good results? 

Ans.—The draught should not be less than .5 inch. 
Better results may be obtained with a draught of .7 inch. 

Ques. 395.—If the test is made for the purpose of 
determining the efficiency of the boiler and setting as a 
whole, including grate, draught, etc., and also for compar* 



Fig. 100 . Draught Gauge. 




















































152 


QUESTIONS AND ANSWERS 


ing the heating qualities of different kinds of coal, what 
must the result be based upon? 

Ans.—Upon the number of pounds of water evapo¬ 
rated per pound of coal burned. 

Ques. 396.—What is implied in the expression “per 
pound of coal burned” as used in this connection? 

Ans.—It includes not only the purely combustible 
matter in the coal, but the non-combustible also, such as 
ash, moisture, etc. Some varieties of Western coal con- 
tain as high as 12 to 14 per cent of moisture, and the 
ability of the furnace to extract heat from the mass is to 
be tested, as well as the ability of the boiler to absorb and 
transmit that heat to the water. 

Ques. 397.—If the test is to determine the efficiency 
of the boiler itself as an absorber and transmitter of heat, 
what must be the factor for working out the result? 

Ans.—The weight of the combustible alone must be 
considered. 

Ques. 398.—When making a series of tests for the 
purpose of comparing the economical value of different 
kinds of coal, what conditions should prevail? 

Ans.—The conditions should be as nearly uniform a i j 
possible; that is, let the tests all be made under ordinary 
working conditions, and with the same boiler or boilers, 
and if possible with the same fireman. 

Ques. 399.—What is meant by the term “equivalent 
evaporation,” as applied to the results of an evaporation-' 
test? 

Ans.—The term “equivalent evaporation,” or t -e 
evaporation from and at 212 degrees, assumes that the 


BOILER OPERATION 


153 


feed-water enters the boiler at a temperature of 212 
degrees and is evaporated into steam at 212 degrees tem¬ 
perature, and at atmospheric pressure, as, for instance, 
if the top man-hole plate were left out, or some other 
large opening in the steam-space of the boiler allowed the 
steam to escape into the atmosphere as fast as it was 
generated. 

Ques. 400.—Why is it necessary to introduce this 
feature into calculations of the results of evaporation- 
tests? 

Ans.—Owing to the variation in the average tem¬ 
perature of the feed-water used in different tests, and also 
the variation in the average steam-pressure, it is 
absolutely necessary that the results of all tests be 
brought by computation to the common basis of 
212 degrees in order to obtain a fair and just comparison. 

Ques. 401.—Describe the method of calculation by 
which this is done. 

Ans.—Suppose an evaporation-test to have been made, 
and that the average steam-pressure by the gauge was 
85 pounds, which equals 100 pounds absolute pressure, 
and that the average temperature of the feed-water was 
141 degrees. By reference to Table 1, Chapter 1, it will 
be found that in a pound (weight) of steam at 100 pounds 
absolute pressure there are 1,181.1 heat units or thermal 
units, and in a pound of water at 141 degrees temperature 
there are 109.9 heat units. It therefore required 
1,181.1 — 109.9 = 1,071.9 heat units to convert 1 pound 

« 

of feed-water at 141 degrees temperature into steam at 
85 pounds gauge, or 100 pounds absolute pressure. Now 





154 


QUESTIONS AND ANSWERS 


to convert a pound of water at 212 degrees temperature 
into steam at atmospheric pressure and 212 degrees tem¬ 
perature, requires (according to Table l) 965.7 heat units, 
and the 1,071.9 heat units would evaporate 1,071.9 -f- 965.7 
= 1.11 pounds of water from and at 212 degrees. The 
1.11 is the factor of evaporation for 85 pounds gauge 
pressure, and 141 degrees temperature of feed-water. 

Ques. 402.—What use is made of this factor of evap¬ 
oration in the calculation? 

Ans.—One of the results of the test was “weight of 
water corrected for moisture in the steam,’’ and by mul¬ 
tiplying this result by the factor of evaporation, the 
“equivalent evaporation” is ascertained. 

Ques. 403.—Upon what is the factor of evaporation 
based, in any test? 

Ans.—Upon the steam-pressure and the temperature 
of the feed-water. 

Ques. 404.—Give the formula for finding this factor 
for any test. 

pj-_p 

Ans.—The formula is: Factor -,in which H = 

965.7 

total heat in the steam, h = total heat in the feed-water, 
and 965.7 = the number of heat units in a pound of 
steam at atmospheric pressure and 212 degrees tempera¬ 
ture. Table 7 gives the factor of evaporation, already 
calculated, for various pressures and temperatures. 

Ques. 405.—If it is desired to ascertain the cost of 
coal for generating the steam used for operating an engine 
that uses 30 pounds of steam per horse-power per hour, 
what is the method of calculation? 



BOILER OPERATION 


155 


Ans.—If the engine uses 30 pounds of steam per horse¬ 
power per hour, and it has been found by the test that 
1. pound of the coal used would evaporate 9 pounds of 
water into steam of the pressure at which it is supplied to 
the engine, the actual consumption of fuel by the engine 

Table 7 


Factors of Evaporation 


Feed Water 
Temperature 

Gauge 
Press. 50 lbs. 

Gauge 
Press. 60 lbs. 

Gauge 

Press. 70 lbs. 

Gauge 

Press. 80 lbs. 

Gauge 

Press. 90 lbs. 

Gauge 

Press. 100 lbs. 

Gauge 

Press, no lbs. 

Gauge 

Press. 120 lbs. 

Gauge 

Press. 140 lbs. 

1 

212° 

I.027 

I.030 

I.032 

I.035 

I.037 

I.039 

1.041 

I.043 

I.047 

200° 

I.039 

I.042 

I 045 

I.047 

I.050 

I.052 

1.054 

I.056 

I.059 

I 9 I° 

1.049 

I.052 

I.054 

1.057 

I.059 

I.061 

1.063 

I.065 

1.069 

182° 

1.058 

1.061 

1.064 

I.066 

1.069 

I.071 

1-073 

1-075 

1.078 

173° 

1.067 

I.070 

1-073 

1.076 

I.078 

I.080 

1.082 

I.0S4 

1.087 

164° 

I.077 

I.080 

1.083 

I.085 

I.087 

I.090 

1.091 

I.093 

I.097 

152° 

1.089 

I.O92 

1.095 

1.098 

I.IOO 

1.102 

1.104 

I.I06 

1.109 

143° 

I.099 

1.102 

1.105 

1.107 

1.109 

I.III 

1.113 

I.H5 

1.119 

134° 

1.108 

I. Ill 

1.114 

I.I16 

1.119 

1 . 121 

1.123 

I-I25 

1.128 

125° 

1.118 

I.I2I 

1.123 

1.126 

1.128 

1.130 

1.132 

I.I34 

I-137 

113 0 

1.130 

1.133 

1.136 

1.138 

1.140 

I-143 

1.145 

I.146 

1.150 

104° 

1.138 

1.142 

I.I45 

1.148 

1.150 

I.I52 

1. 154 

I.156 

I-159 

95° 

1.149 

1.152 

I-I54 

1.157 

1.159 

I.l 6 l 

1.163 

I.165 

1.169 

86° 

1.158 

I. l6l 

1.164 

1.166 

1.169 

I.I7I 

1.173 

I-174 

1.178 

77° 

1.167 

1.170 

i- 1 73 

I.176 

1.178 

1.180 

1.182 

I.184 

1.187 

65° 

1.180 

I.183 

1.186 

I.188 

1.190 

I.I92 

1.194 

1.196 

1.200 

56° 

1.189 

1.192 

1.195 

1.197 

1.200 

1.202 

1.204 

I.206 

1.209 

47° 

1.199 

I. 201 

1.204 

I.207 

1.209 

I.2II 

1.213 

I. 2 I 5 

1.218 

38° 

1.208 

I.2II 

1.214 

1.216 

I. 2 l 8 

1.220 

1.222 

I.224 

I. 228 


would be as follows: 30 -4- 9 = 3.33 pounds of coal per 
horse-power per hour, which, multiplied by the total horse¬ 
power developed by the engine, will give the total weight 
of coal consumed in one hour’s run. 

Ques. 406.—What is the meaning of the expression 
“boiler horse-power?” 




























156 


QUESTIONS AND ANSWERS 


Ans.—The latest decision of the American Society of 
Mechanical Engineers regarding the horse-power of 
a boiler is “that the unit of commercial horse-power de¬ 
veloped by a boiler shall be taken as 34^2 units of evapor¬ 
ation. ” That is, 34>^ pounds of water evaporated per 
hour from a feed temperature of 212 degrees into steam 
of the same temperature. 

This standard is equivalent to 33,317 heat units per 
hour. It is also practically equivalent to an evaporation 
of 30 pounds of water from a feed temperature of 
100 degrees Fahrenheit into steam of 70 pounds gauge- 
pressure. 

Ques. 407.—According to this rule, what would be 
the horse-power of a boiler in which during a 10-hour 
test, the evaporation from and at 212 degrees was found 
by calculation to have been 86,250 pounds of water? 

Ans.—The horse-power developed would be 86,250 
10“?“ 34.5 = 250 horse-power. 

Ques. 408.—In what way can the maximum economy 
in the consumption of coal be obtained? 

Ans.—There is only one way, and that is by keeping 
a continuous supply of coal on the fires and admitting a 
regular and sufficient quantity of air for its combustion. 

Ques. 409.—Can these conditions be reached by hand 
> firing? 

Ans.—They can not, no matter how careful and skil¬ 
ful the firemen may be. 

Ques, 410.—Mention two of the principal disadvan¬ 
tages attending hand firing. 

Ans.—First, durin the time of firing the furnace 


50ILER OPERATION 


157 


door is wide open, thus admitting a large volume of cold 
air; second, immediately after throwing in a fresh supply 
of coal, there is a sudden generation of gas, a large per¬ 
centage of which escapes without being entirely consumed, 
and much heat is thus wasted. 

Ques. 411.—What are the principles governing the 
operation of mechanical or automatic stokers? 

Ans.—First, a continuous supply of coal and air; 
second, thorough regulation of the supply of fuel and air, 
according to the demand upon the boilers for steam; 
third, the intermittent opening and closing of the furnace 
doors is entirely prevented. 

Ques. 412.—What are some of the disadvantages 
attending the use of mechanical stokers? 

Ans.—First, the great cost of installing them; setond, 
in case of a sudden demand upon the boilers for more 
steam, the mechanical stoker can not respond as promptly 
as in hand firing; third, the extra cost for power to 
operate them. 

Ques. 413.—How many different classes of mechanical 
stokers are in use? 

Ans.—Four general classes. 

Ques. 414.—Describe the construction and operation 
of stokers belonging to Class 1. 

Ans.—The grate consists of an endless chain of short 
bars, that travels in a horizontal direction from the front 
to the back of the furnace, over sprocket wheels operated 
either by a small auxiliary engine or by power derived 
from an overhead line of shafting in front of the boilers. 
The motion of the endless chain of grates is of course very 





158 


QUESTIONS AND ANSWERS 



















BOILER OPERATION 


159 


slow, but it is continuous and regular, receiving the supply 
of coal at the front and depositing the ashes at the baos 
end, where they drop into the ash-pit. 



Ques. 415.—What type of stokers is included il 
Class 2 ? 

Ans.—Stokers having grate-bars somewhat after the 
ordinary hand-fired type, but having a continuous motion 






























160 


QUESTIONS AND ANSWERS 


uo and down, or forward and back. Although this 
motion is slight, it serves to keep the fuel stirred and 
loosened, thus preventing the fire from becoming sluggish 
Ques. 416.—What position do the grate-bars in 
Class 2 occupy? 



Fig. 103. Vicafs Mechanical Stoker. 


AftS. —Either horizontal, or slightly inclined, and their 
constant motion tends to gradually advance the coal from 
the front to the back end of the furnace. 

Ques. 417.—What kinds of stokers are included in 
Class 3 ? 

Ans.—Stokers in which the grates are steeply inclined 





























































































BOILER OPERATION 


161 


The coal is fed onto the upper ends of the gates, which, 
having a slow motion, gradually force the coal forward as 
fast as required. In some stokers of this class, as, for 
instance, the Murphy, the grates incline from the sides 
towards the middle of the furnace, but in the majority of 
cases the inclination is from the front towards the back. 



Fig. 104. The Murphy Automatic Furnace. 


Ques. 418.—What is the leading feature governing the 
operation of stokers belonging to Class 4 ? 

Ans.—The coal is supplied from underneath the grates, 
and is pushed up through an opening left for the purpose 
midway of the length of the furnace. 4 he gases, on 
being distilled, come in contact immediately with the hot 
bed of coke on top, and the result is good combustion. 
Ques. 419.—What are stokers belonging to Class 4 

called? 













































































162 


QUESTIONS AND ANSWERS 


Ans.—Under-feed stokers. 

Ques. 420.—What methods are employed for forcing 
the coal up into the furnace with under-feed stokers? 



Ans.—Steam is the active agent, either by means of 
a steam-ram, or a long, slowly revolving screw, driven 
by a small engine- 
























BOILER OPERATION 


163 


Ques. 421.—How is the air supplied when an under¬ 
feed stoker is used? . 



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Ans.—Forced draught is employed, and the air is 
blown into the furnace through tuyeres. 

Ques. 422.—How is the coal supplied to mechanical 

stokers, other than the under-feed type? 

Ans.—In two ways; either by being shoveled by hand 














264 


QUESTIONS AND ANSWERS 


into hoppers in front of and above the grates, or, as is the 
case in most of the large plants using them, it is elevated 
by machinery and deposited in chutes, through which it 
is fed to each boiler by gravity. The coal used in 
mechanical stokers is in the form of screenings or nut 
coal. 

Ques. 423.—Have mechanical stokers for feeding coal 
been applied in the marine service to any great extent? 

Ans.—They have not, up to the present time. 



Fig. 107. Jones Under-feed Stoker, Having a Steam Ram. 

Ques. 424.—In what way is it possible to successfully 
use automatic or mechanical stokers on marine boilers? 

Ans.—By the use of liquid fuels, such as petroleum, 
blast-furnace oil, tar oil, etc. 

Ques. 425.—Of what does petroleum consist? 

Ans.—Petroleum consists practically of carbon, 
hydrogen, and oxygen, in the following proportions: 
Carbon, 85 per cent; hydrogen, 13 per cent, and oxygen, 
2 per cent. 

Ques. 426.—What is the heating value of 1 pound of' 
petroleum? 





BOILER OPERATION 


165 


Ans.—About 20,000 heat units, or about one-third 
’ more than the best coal. 

Ques. 427.—How is petroleum fed to the furnaces? 
Ans.—By being forced through nozzles having two 
1 or three holes, or annular spaces, from one of which the 
petroleum flows out, under pressure, while a jet of steam 
or compressed air issuing from another orifice catchy 
the oil and “pulverizes” it into a fine spray, in which 
form it strikes the fire. The air for combustion is 
admitted through a third orifice, or if not thus supplied. 



Fig. 108. Sectionae View of Jones Under-feed Stoker. 


the air for combustion is admitted by suitable orifices in 
the furnace front, 

Ques. 428.—How is the furnace arranged for burning 
petroleum? 

\ 

Ans.—A layer of broken fire-brick or asbestos is 
placed on the grate, and fire-brick screens, or bafflers, 
are placed in the way of the flame, thus providing a red- 
hot surface against which it impinges. Otherwise the 
combustion would be greatly hindered by the compara¬ 
tively cool surfaces of the boiler-plates and tubes. 

Oues. 429.—What agent has been found to be the best 










166 


QUESTIONS AND ANSWERS 


for pulverizing the petroleum and spraying it into the 
furnace? 

Ans.—Compressed air, slightly heated. 

Ques. 430—What is one of the disadvantages attend¬ 
ing the use of steam for this purpose? 

Ans.—The danger of the flame being extinguished by 
water that is sometimes carried over with the steam. 



Fig. 109. Petroleum Burner eor Boieer Furnace. 


Ques. 431.—How is the oil supplied to the nozzles? 

Ans.—By means of pumps that draw it from the 
bunkers and discharge it into a reservoir, and from 
thence it is fed to the burners. 

Ques. 432.—What are the advantages in favor of 
petroleum fuel, especially for the marine service? 

Ans.—First, superior evaporation, and, as a conse¬ 
quence, great reduction in the weight of fuel to be carried; 

































































































BOILER OPERATION 


167 


sfcond, less space occupied by the fuel and ease of ship¬ 
ping it into the bunkers; third, reduction of stoke-hold 
force, also less space required in the stoke-hold; fourth, 
regularity of combustion and no reduction of power, due 
to cleaning fires, they being always clean and in a good 
condition; fifth, increased durability of boilers, owing to 
the fact that there are no variations of temperature, due 
to opening fire-doors, for coaling or cleaning; sixth, 
greater control over the expenditure of fuel, consequently 
less waste of steam at the safety valves, also less danger 
of a short supply of steam in case of a sudden demand 
upon the boilers. 

Ques. 433.—What are some of the principal objections 
to its use on board of vessels? 

Ans:—First, limited supply; second, vessels proceed¬ 
ing on long voyages could not, with present facilities, 
replenish their bunkers when required; third, danger of 
the generation of inflammable gases; fourth in war-ships 
the risk of possible loss of the fuel, in the event of injury 
to the bunker containing it. 

Ques. 434.—Has the combination of coal and petro¬ 
leum, in the same furnace, ever been attempted? 

Ans.—Experiments along this line are being made in 
the British and other navies. 

Ques. 435.—How are the furnaces fitted for this 
purpose? 

Ans.—The same as for hand firing with coal, and in 
addition, a number of nozzles are placed in the front 
above the fire for injecting the petroleum over the incan¬ 
descent coal. 








168 


QUESTIONS AND ANSWERS 




Ques. 436.—Upon what does the efficiency of a steam 
ship, or of a manufacturing establishment in which stean 
is used for power, largely depend? 

Ans.—Upon the condition of the boilers and the car 
and labor expended for their preservation. 

Ques. 437.—What was formerly one of the most dan 
gerous and active agents in the deterioration of boilers 
especially in the marine service? 

Ans.—Corrosion of the boiler-plates and stays. 

Ques. 438.—What was found, by a long series c: 
experiments, to be the principal cause of this corro* 
sion? 

Ans.—The action of the fatty acids evolved b} 
saponification from the heated tallow and vegetable oils, 
used at the time for the internal lubrication of the cylin¬ 
ders and valve-chests. 

Ques. 439.—How were these oils carried into the 
boilers? 

Ans.—In condensing systems, where the water of con¬ 
densation was used for feed-water, the waste oil in the 
exhaust steam mingled with the feed-water and was 
carried into the boilers. 

Ques. 440.—How has the danger from this source been 
largely obviated in late years? 

Ans.—By the use of mineral oils for internal 
lubrication. 

Ques. 441.—In what other way has the danger of 
corrosion been lessened? 

Ans.—By the use of mild steel instead of iron plates 
in the construction of boilers. This steel is made by the 





BOILER OPERATION 


169 


re 


Seimens-Martin process, and is much stronger than iron 
and less liable to corrosive action. 

Ques. 442.—Of what material are marine boilers now 
made entirely? 

Ans.—Of steel, except the tubes, which are usually 
made of iron in the mercantile service. Steel tubes are 
used in war-ships. The furnaces and internal parts, that 
have to be welded or flanged, are made from specially 
soft steel plates. 

Ques. 443.—What is the principal cause of corrosion 
in boilers at the present time? 

Ans.—Oxidation of the plates, which results from 
contact with moisture and air, either carried in with the 
feed-water, or existing in the atmosphere when the boilers 
are empty. 

Ques. 444.—What conditions must exist in order that 
corrosion shall take place from this cause? 

Ans.—The simultaneous presence of both air and 
water, because neither dry air nor fresh water in which 
there is absolutely no air has any chemical action on steel 
or iron. Air dissolved in water is especially active, and 
the action is increased by the presence of various 
n chlorides, such as magnesium and sodium. 

Ques. 445.—Are there any other causes that tend 
toward the corrosion of boilers, internally? 

Ans.—There are; for instance, hot sea-water, even 
when entirely deprived of air, has some action on steel 
and iron. It has been found that at the high tempera- 
5 tures now common in boilers, the chloride of magnesium 
e contained in sea-water is decomposed by the heat and 









170 


QUESTIONS AND ANSWERS 


gives off hydrochloric acid, the evolution of acid bei:; 
accelerated with increase of density. 

Ques. 446.—Should sea-water be admitted to boilers f 
it is possible to prevent it? 

Ans.—It should not; but if a portion is used, it s 
important that sufficient alkali, preferably lime, 
admitted with the feed-water to render the water in t i 
boilers slightly alkaline by the litmus test. 

Ques. 447.—Does galvanic action, due to differences ’ 
the material used in the construction of the boilers, coi 
duce towards corrosion? 

Ans.—Galvanic action is probably a minor cause : 
corrosion. 

Ques. 448.—What are some of the methods th 
may be employed for the prevention of corrosion 
boilers? 

Ans.—First, the admittance of air into the boile 
while at work should be prevented as much as possibl 
This may be done by having a tank, called the feed-tan 
into which the air-pumps may discharge its water, ai 
from which the feed-pumps can draw their water for suj| 
Plying the boilers. The feed-pumps should be independe 1 
pumps, which can be so regulated in speed as to l[ 
always fully supplied with water and never to empty tl. 
feed-tank and so suck in and discharge air into the boiler 
Second, the complete exclusion of sea-water from tl 
boilers if possible. The waste of feed-water should 1 
made good by evaporators and a reserve of fresh watt 
in tanks. Third, mineral oils, which consist of hydroca: 
ijons only, should be used exclusively for lubrication ( 










BOILER OPERATION 


171 


jail internal parts of the engines and pumps requiring 
lubrication. 

Ques. 449.—How may the injurious effects of galvanic 
action be neutralized? 

Ans.—By the suspension of zinc slabs in various 
.parts of the boiler, both below the water-line and also in 
the steam-space. Then if there be any galvanic action 
the zinc slabs will be attacked instead of the material of 
; *he boiler itself. 

! 



Fig. 110 . Method oe Suspending Zinc Scabs. 


Ques. 450.—What is an important point to be 
observed when placing these zinc slabs? 

A ns .—They should be in actual bright contact with 
the material of the boiler and they should be well distrib¬ 
uted, so that every portion of the interior surface of the 
boiler is protected. 

Ques. 451.—What is the theory of the action of these 
zinc slabs, in preventing galvanic corrosion? 




































172 


QUESTIONS AND ANSWERS 


Ans.—Zinc is an electro-positive metal, and it beinj 
suspended in the boiler causes the steel of the boiler t< 
become electro-negative and thus any corrosive agent i 
induced to attack the zinc, leaving the steel uninjured 



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o 

55 

o 

w 

to 

«* 

W 

a 

o 

« 

ta 

55 

to 

< 

3 

to 

O 

55 

O 

s 

8 

to 


o 

fa 


This preservative action can only take place when the 
boilers have water in them and the zinc slabs fitted in the 
steam-space act only when the boilers are completely filled 
with water. 


























































































































CHAPTER VI 


TYPES OF ENGINES—CLASSIFICATION 

Ques. 452.—Into what three general classes may 
larine and stationary engines be divided? 

Ans.—First, simple; second, compound; third, triple, 
r quadruple expansion. 

Ques. 453.—What causes the piston of a steam-engine 
> move back and forth in the cylinder? 



Fig. 112. Cross Compound Direct Connected Coreiss Engine, 

Allis Chalmers Co. 

Ans.—The expansive force of the steam that is 
knitted alternately behind the piston, at either end of the 
linder. 

Ques. 454.—Describe the action of the steam in a 
nple engine. 

Ans.—In a simple engine the steam is used in but one 
linder, and from thence it is exhausted, either into the 
mosphere or into a condensor. 

173 





174 


QUESTIONS AND ANSWERS 


Ques. 455.—What is the leading characteristic of j 
compound engine? 

Ans.—In a compound engine the steam is made to dj 
work in two or more cylinders befo r e it is allowed t^ 

exhaust. ' 

Ques. 456.—How is this accomplished? 

Ans.—The compound engine is fitted with two, and i 
some cases with three cylinders. The cylinder into whicj 
steam at boiler pressure is admitted is termed the higl! 
pressure cylinder and is the smallest of the group, i 



Fig. 113. Tandem Compound Engine, Buckeye Engine Co. 


diameter. The exhaust passage (or receiver) from th 
cylinder leads directly to the valve-chest of anoth 
cylinder, larger in diameter, termed the low-pressu 

| 

cylinder, and thus conducts the exhaust from the hid 
to the low-pressure cylinder, wherein it again serves 

i 

working steam, and if the cylinders are properly propc 
tioned for the pressure, the amount of work done in ea 
cylinder will be the same. 

Ques. 457.—How many kinds of compound engin 
are in use generally? 












TYPES OF ENGINES-CLASSIFICATION 


17b 





of 

tod( 


Ans.—Two kinds: First, the cross compound, in 
which the cylinders stand parallel, each having its indi¬ 
vidual cross-head, connecting rod, and valve-gear, and ail 
to a common crank-shaft; second, tandem 


i 

compound, in which the cylinders are tandem to each 
«other, and one piston rod, cross-head, connecting rod, and 
valve-gear is common to both, although each cylinder has 


Fig 114 - Reynolds Combined Vertical and Horizontal Engine. 12.000 Horse-Power 

Cylinders. 44x88x60. 




















17G 


QUESTIONS AND ANSWERS 


its own valve or valves for controlling the admission and 
release of the steam. 


Ques. 458.—What is implied in the expression “triple 


expansion?” 

Ans.— l riple expansion means that the steam has been 
allowed to expand through three successive stages, doing 



Fig. 115. Shows a Triple Ex¬ 
pansion Engine in which the 
High Pressure is Tandem with 
the Intermediate Cylinder. 


J 


•3 

I 





Fig. 115a. Shows the Ordinary Ai 
rangement oe Cylinders for a Tr 
ple Expansion Engine. 


a fixed amount of work in each stage, before release rcc 


occurs. 

Ques. 4o9. IIow many cylinders are required on a 
triple-expansion engine? 

Ans.—Never less than three, and for large, high-speed 
engines it often becomes necessary to have two low- 


S' 

Ik 


ISC 






































































TYPES OF ENGINES—CLASSIFICATION l 1 ?? 


pressure cylinders, thus making a four-cylinder triple- 
expansion engine. 

Ques. 460.—Are four cylinder triple-expansion en¬ 
gines much in use? 

Ans.—They are in the marine service, and especially 
n the British navy, and they are also used to a large 
extent in the mercantile service. 

Ques. 461.—Describe the action of the steam in a 
[uadruple-expansion engine. 



Ans.—In a quadruple-expansion engine, the expansion 
>f the steam is divided up into four stages by causing it 
o pass through four successive cylinders, termed 
espectively the high-pressure, first intermediate, second 
ntermediate, and low-pressure. In some of the larger 
ngines of this type there are two low-pressure cylinders, 
hus making five cylinders in all. 

Ques. 462.—What pressures of steam are usually 
ised in this type of engine? 




















































& 8 


QUESTIONS AND ANSWERS 


Ans.—From 200 to 250 pounds per square inch. 

Ques. 463.—What are some of the advantages that 
ire to be gained in the use of steam by stage expansion? 



































































































































































































































































































































































TYPES OF ENGINES-CLASSIFICATION 179 

Ans.—First, that the cylinder into which steam 
directly from the boiler is admitted is never open to the 
cooling influence of the atmosphere, or condensor, hence 
there is not so much cooling and condensation of the 
entering steam; second, the steam that is condensed and 
reevaporated in the first cylinder reappears as working 
steam in the second cylinder; third, the loss from con¬ 
densation in the second and third cylinders is also reduced, 

V 

owing to the smaller range of temperature, between 
admission and exhaust in those cylinders. 

Ques. 464.—What are the mechanical advantages of 
compound and triple-expansion engines, for heavy duty? 

Ans.—First, the facility with which high rates of 
expansion may be carried out without bringing excessive 
strains and stresses on the framing of the engine; second, 
a greater uniformity of twisting moment on the shaft. 

Ques. 465.—What are the usual ratios of cylinder 
volumes in compound and triple and quadruple-expansion 
engipes? 

Ans.—For compound engines 1 to 4 between high and 
low-pressure cylinders. For triple-expansion engines, 
the ratios are about 1, 3 and 7, for high, intermediate 
and low-pressure cylinders. For quadruple-expansion 
'engines the ratios are as follows: 1, 2, 4/4 and 10/4 for 
I, high-pressure, first intermediate, second intermediate and 
low-pressure respectively. 

Ques. 466.—What is meant by the term receiver, as 
used in connection with the stage-expansion of steam? 

Ans.—In the case of a compound engine the receiver 
is the whole of the space between the high-pressure 






180 


QUESTIONS AND ANSWERS 


piston, when at the end of its stroke, and the back of the 
low-pressure steam-valve, whether it be slide rotative, or 
piston-valve. In the case of a triple-expansion engine, 
the space between the piston at the end of its stroke and 
the back of the intermediate steam-valve is called the 
intermediate receiver, and the space between the inter¬ 



mediate piston at the end of its stroke and the low-pres- 

I 

sure steam-valve is the low-pressure receiver. 


Ques. 467.—What is the usual volume of these 
receivers in modern practice? 

Ans.—After many experiments with large reservoirs 
as receivers, it has been found that all that is necessary 
is a comparatively large exhaust pipe from the exhaust i 





























































































































TYPES OF ENGINES-CLASSIFICATION 181 

orifice of the high-pressure cylinder to the steam inlet of 
the next lower pressure cylinder, it having been demon¬ 
strated that the volume of the exhaust passage and pipe 
from the high-pressure cylinder and the low-pressure 
valve-chest supplied sufficient space to allow for the com¬ 
pression that occurs between release from the high-pres¬ 
sure cylinder and admission to the low-pressure cylinder. 

Ques. 468.—Does this law 
apply in the case of triple and 
quadruple-expansion engines? 
Ans.—It does. 

Ques. 469.—Upon what 
does the power of any stage- 
expansion engine depend? 

Ans.—The power of a 
stage-expansion engine work¬ 
ing at any given rate of ex¬ 
pansion depends entirely upon 
the dimension of its low- 
pressure cylinder or cylinders, 
Fig. 119. Tandem Quadruple Ex- anc [ j s no t affected by the size 

pansion Marine EngineShowing j 

Arrangement of Cyl.nders. q{ j ts high-pressure cylinder, 
which latter, in fact, carries out but one stage in the 
expansion. 

Ques. 470.—What does the capacity of the low-pres¬ 
sure cylinder or cylinders of such an engine require to be? 

Ans.—The same as that of the whole of the cylinders 
of a simple engine of the same power, working at the 
same initial pressure and total ratio of expansion. 

Ques. 471.—Why is this? 










































182 


QUESTIONS AND ANSWERS 


Ans.—For the reason that, since the initial pressures 
and ratios of expansion are the same in bot.i engines, it 
follows that the terminal pressures and volumes must j 
also be identical in both cases. In the simple engine the 
whole of the steam at the end of the stroke fills all of the 

cylinders, while in the compound engine it is contained in 

* 

the low-pressure cylinder or cylinders only, hence the 
capacity of this cylinder must be equal to the capacity of 
all the cylinders of the simple engine. 



Fig. 119a. Quadruple Expansion Engine, with Cylinders as Ordinarily 
Arranged—Arrows Show Course Taken by the Steam. 

Ques. 472.—Why is it necessary in some cases to 
employ two low-pressure cylinders? 

Ans.—For the reason that in very large -engines one 
low-pressure cylinder would be too large and unwieldy, 
therefore it is divided into two equal parts. 

u e s. 17 8. Are compound and triple-expansion 

engines much in use outside of the marine service? 

Ans.—They are to a large extent, owing to the great 
gain in economy over the simple engine. Practically all 
large manufacturing plants them. 













































TYPES OF ENGINES-CLASSIFICATION 


183 


Ques. 474.—What other types of engines are in use 
in the marine service? 

Ans.—The vertical walking-beam engine is largely in 
use on the lakes, bays, and rivers of the United States. 



FitL 120. Belleville Reducing Valve. 


Ques. 475.—What is the leading characteristic of this 
type of engine? 

Ans.—It has usually buj a single cylinder, with a very 































































184 QUESTIONS AND ANSWERS 

long stroke in proportion to its diameter, the length of 
the stroke varying from 7 to 12 feet. 

Ques. 476.—What pressures of steam are usually 
employed in beam engines? 

Ans.—Owing to the fact that the steam is expanded 
in a single cylinder only, the pressure carried is low—50 
to 60 pounds per square inch. 

Ques. 477.—Mention another type of engine that is in 
common use on Western rivers. 



Fig. 121. 


Fig. 121 is a sectional view of the cylinder, steam, and exhaust-chests, an 
the valve-chambers of a Corliss engine. 1 and 2 are the steam-valves and 3 an 
4 the exhaust-valves. The valves work in cylindrical chambers accurately bore 
©ut, the face of the valve being turned off to fit steam tight. They are what 
termed rotative valves, that is, they receive a semi-rotary motion from the wris 
?-,.iate, which in turn is actuated by the eccentric. 


Ans.—The stern-wheel engine, consisting of a pair o, 
engines, one cylinder bn either side of the boat, and 
directly connected to the shaft of the stern-wheel. Like 
the beam engine, the stroke is long in proportion to the 
cylinder diameter. 

Ques. 478.—Are these engines simple or compound: 

Ans.—In former years simple engines were used alto- 



































TYPES OF ENGINES-CLASSIFICATION 


185 


gether, but the later types are compound, either tandem 
or cross-compound. 

Ques. 479.—What styles of valves and valve-gears 
are in use on these engines? 

Ans.—Poppet-valves, actuated by long cam-driven 
levers, are the most generally used. Other styles of 

t ralves, such as rotative valves, common slide and piston - 
r alves, are also quite frequently used. 


Q 


? 

//* 


- J 

c 

w 


B 

jo __ 

( ® ) 

3 ^ 

|jn^ 

p , B : ?r *a 

Fm 


Fig. 122. 


The valve-gear of a Corliss engine with a single eccentric is shown in Fig. 122. 
lie connections of the exhaust-valves with the wrist-plate are positive, and 
e travel of these valves is fixed, being a constant Quantity, but the connection! 
the steam-valves with the wrist-plate are detachable, being under the control 
the governor. 

Ques. 480.—What is meant in speaking of a f~” 
ilalve engine? 

3! Ans.—An engine having two steam-valves and tvi a 
exhaust-valves located near each end of the cylinder. 

Ques. 481.—What type of four-valve engine has met 
with great favor since its introduction? 

Ans.—The Corliss engine, invented by Mr. Geo. H. 
Corliss, of Providence, R. L 










































186 


QUESTIONS AND ANSWERS 


Ques. 482.—What advantage does the four-valv 
engine possess over the single-valve type? 

Ans.—The advantage that each valve may be ad juste 
to a certain degree independently of the others, the steam 
valves tor admission and cut-off and the exhaust-valve 
for compression and release. 

Ques. 483.—What is one of the oldest forms of valve 
and one that is still used extensively, especially o 
marine engines? 

Ans.—The D slide-valve. 


0 L c L 



Fig. 123. 


Fig 123 rep resents a slide-valve at mid-travel. S P—S P are the stea 
ports and E P is the exhaust-port; the projections marked x at each foot c 
the arch inside the valve represent inside lap, and may be added to or take 
trom the inside edges of the valve, according as more or less compression 
desired. The dotted lines O E—O L represent outside lap. 

Ques. 484.—What are the functions of the slide 
valve? 


Ans.—It controls the admission, expansion and releas 
of the steam and the closure of the exhaust. 

Ques. 485.—Upon what does the development of th< 
full power of the engine and its efficient and economica 
use of steam, as well as its regular and quiet action 
largely depend? 

Ans.—-Upon the correct adjustment of its valve oil 
valves. 












TYPES OF ENGINES-CLASSIFICATION 


187 


Ques. 486.—How is the slide-valve fitted to the 
cylinder? 

Ans.—The slide-valve has a flat face and it works on 
i.the corresponding flat face of the cylinder. In the 
.cylinder face there are three passages called ports, the 
two smallest, called steam-ports, leading to each end of 
jthe cylinder, and the larger one, called the exhaust-port, 
Reading to either the receiver, condensor, or the atmos¬ 
phere, as the case may be. The valve is contained in a 
steam-tight chest or casing, either cast with the cylinder, 



Fig. 124. 


Fig. 124 shows the slide-valve in Jthe position of lead—exhaust opening has 
t -Iso occurred at the opposite end of the cylinder. The arrows show the course 
i f the steam, also the direction in which the valve is traveling. 

i _ 

i! 

>r bolted to it. This casing or valve-chest is filled with 
ive steam while the engine is working. 

Ques. 487.—How must the slide-valve be constructed, 
n order that it may properly perform the four important 
unctions of admission, cut-off, release, and exhaust 
:losure? 

Ans.—It must have lap and lead. 

Ques. 488.—What is lap? 

t 

Ans.—Lap is the amount that the ends of the valve 
iroject over the edges of the ports when the valve is at 
nid-travel. 











188 


QUESTIONS AND ANSWERS 


Ques. 489.—What is steam lap, or outside lap? 

Ans.—The amount that the end of the valve projecl 
over the outside edge of the steam-port. 

Ques. 490.—What is inside or exhaust lap? 

Ans.—The lap of the inside or exhaust edge of th 
valve over the inside edge of the port. 

Ques. 491.—What is lead? 

Ans.—The amount that the steam port is open whe 
the piston is just commencing its stroke. This is th 
instant of admission. 

Ques. 492.—When is the instant of cut-off? 



/ Z 


Fig. 125. 

Fig. 125 shows the slide-valve at the end of its travel—full port opening 

Ans.—When the admission of steam to the cylinder i 
stopped by the steam edge of the valve closing the stearr 
port and the piston is pushed the balance of the stroke b 
the expansion of the steam admitted before cut-o 
occurred. 

Ques. 493.—When is the instant of compression? 

Ans.—When the two inside or exhaust edges of th 
valve coincide with the inner edges of the ports, thepisto 
being near the end of its stroke and the valve at mid 
travel. 

Ques. 494.—When is the instant of release? 







TYPES OF ENGINES-CLASSIFICATION 


189 


Ans.—When the inner edge of the valve commences to 
>pen the steam-port to the exhaust-passage. 

Ques. 495.—What is the advantage gained by com- 

iression? 

Ans.—A portion of steam is confined ahead of the 
)iston, thus forming an elastic cushion to absorb the 
nomentum of the piston and other moving parts con- 

lected with it and bring all to rest Quietly at the end of 

9 

, he stroke. 

Ques. 496.—How may this compression be increased 
>r diminished? 



-— 




Fig. 126 . 

Fig. 126 illustrates the instant of cut-off. The valve is now traveling in the 
opposite direction. 

Ans.—By adding to or taking away from the inside 
ap of the valve. 

Ques. 497._What is the object of giving a valve lead? 

A ns ._The effect of lead is to cause the engine to be 

luick and not to lag at the beginning of the stroke. The 
live steam admitted through the lead opening also assists 

in forming a cushion for the piston at the end of the 

» 

stroke. 

Ques. 498._Do the principles governing the adjust- 

ment and action of the slide-valve necessarily have to be 
applied in the adjustment and action of rotative, piston, 













190 


QUESTIONS AND ANSWERS 


and other forms of valves for controlling the distributor 
of steam in the cylinders of engines? 

Ans.—They do. The same general principles appl} 
in all cases. 

Ques. 499.—How is motion generally imparted to the 
slide-valve or other types of valves? 

Ans.—By means of an eccentric, which is simply a cir¬ 
cular cast-iron or cast-steel sheave having a hole bored in 
it eccentrically with its own circumference, and large 
enough to permit of its being fitted on the engine shaft. 
The eccentric-sheave is either keyed on the shaft or held 



Fig. 127. 

Fig. 127 shows the slide-valve at the instant of compression. 


in its place by set-screws, and therefore revolves with the 
shaft. On the circumference of the eccentric, which is 
of sufficient width to present a good bearing surface, a 
ring, called the eccentric-strap, works, and attached tc 
this ring is the eccentric-rod, which is either directly con¬ 
nected to the valve-rod, or valve-stem, or else imparts* 
motion to the valve through the agency of a rocker-arm, 
and in many engines a link motion is used. The center 
of revolution of the eccentric being several inches apart 
from its center of formation, will, when the sheave 
revives with the shaft, cause the eccentric to convert the 













TYPES OF ENGINES-CLASSIFICATION 


191 



• i 

• i 


• i 


• t 

:• 
■ • 
11 

• * 


)tary motion into a reciprocating motion, which through 
le agency of the rod is imparted to the valve or valves 
f Ques. 500.—What is meant 

I 

by the throw of an eccentric? 

Ans.—The distance be¬ 
tween the center of the eccen¬ 
tric-sheave and the center of 
the crank-shaft. This dis¬ 
tance is also called the radius 
of eccentricity. 

Ques. 501.—What is meant 
by eccentric position? 

Ans.—The location of the 
highest point of the eccentric 
relative to the center of the 
crank-pin, expressed in de¬ 
grees. 

Ques. 502.—What is ang¬ 
ular advance? 

Ans.—The distance that 
the high point of the eccentric 
is set ahead of a line at right 
angles with the crank, in other 
words, the lap angle plus the 
lead angle. 

Fig. 128 . Ques. 503.—If a valve had 

Fig. 128 shows an eccentric with i i j w li a f 

strap and rod. E is the sheave, neitlier lap nor lead, Wlldl 
; center of which is shown at D. , . « ,. ... r .« 

is the center of the shaft. The would be the position 01 the 
tance A D represents the throw of 

; eccentric and twice that distance ^jp-h point of the eccentric 
aals the travel of the end B of the ° * 

Itfic sfrap e lme A F ‘ S 1S the ec * relative to the crank? 





















192 


QUESTIONS AND ANSWERS 


Ans.—It would be on a line exactly at right angle 
with the crank, as, for instance, the crank being a 
0 degrees, the eccentric would stand at 90 degrees. 

Ques. 504.—How is the reversing of modern marim 
engines usually effected? 

Ans.—By means of the link 
eccentrics. 

Ques. 505.—How many varieties 
of links are in use? 

Ans.—Three, the slotted link, 
the solid-bar link and the double¬ 
bar link. 

Ques. 506.—Describe the slotted 
link. 

Ans.—It is a curved bar with a 
slot cut in it, in which the link-block 
is fitted. This link-block is attached 
to the valve-rod by a pin, about 
which an oscillating motion of the 
block occurs. Two projectoins are 
formed on one side of the link, to 
which the eccentric rods are connected. 

Ques. 507.—Describe the solid-bar link. 


motion, using tw< 



Ans The solid-bar link consists of a simple, curved, 
rectangular bar, with eyes formed at each end, for .on, 

necting the eccentric-rods. The solid bar passes through 
the block. 

Ques. 508. What is the general plan of the double* 
. bar link? 

Ans.—It consists af a nair Q f curved steel bars ioinec 








TYPES OF ENGINES-CLASSIFICATION 


193 



it the ends and kept a certain distance apart by distance 
)ieces. Projecting pins are formed on the link-bars, two 
>n each side, for the attachment of the eccentric-rods. 
The ends of the eccentric-rods are forked and contain each 
wo adjustable bearings, which embrace the pins on each 
.ide of the link. The link-block is a steel or iron pin, 
liding between the bars, and having projections on each 


ide which embrace the link-bars and through which they 
oars slide, on adjustable gun-metal liners. 

Ques. 509.—Why is it necessary that the link shouV 

>e curved? 

Ans.—For the reason that it is used not only foi 
eversing the engine, but also for working steam expan- 
ively, and therefore its shape must be such that when the 
dock is in any intermediate position the center of the 
'ravel of the valve will always be constant, otherwise the 


Fig. 130. Solid Bar Link. 



























QUESTIONS AND ANSWERS 


t94 

distribution of the steam to the two ends of the cylinder 
tyould not be evenly divided. 

Ques. 510.—What is the slip of the link? 

Ans.—A slight oscillating movement of the link on its 
block. 

Ques. 511.—What is it that fixes the curvature of the 
link? j 

Ans.—The length of the eccentric-rod; that is, the 
curve of the link is a circular arc, of a radius equal to the 



Fig. 131. Plan View oe Double-Barbed Lins. 


distance between the center of the eccentric and center of 
the pin at the end of the rod. 

Ques. 512. —Is there a type of reversing valve-gear 
that employs but one eccentric? 

Ans.—There is, viz., the Marshall radial valve-gear. H 
Ques. 513.—It there a type of reversing valve-gear int 
which eccentrics are dispensed with? 

Ans.—There is, viz., the Joy valve-gear, by which the 
motion of the valve is derived from the connecting rod, 
through the medium of a vibrating link, one end of which 


























































TYPES OF ENGINES—CLASSIFICATION 


195 


is jointed to the connecting rod while the other end is 
constrained to move in a horizontal or vertical direction 
by the action of a radius rod. This motion is horizontal 
if the engine is a vertical engine, or vertical if the engine 
is horizontal. One end of another rod works on a pin in 
the vibrating link and near the other end of this rod is a 
fulcrum carried by a pin attached to sliding blocks on 
each side, working in sectors, which are carried by the 
reversing shaft. Motion is communicated to the valve 



Fig. 132. 


Fig. 132 shows details of the construction of the link-block for a double- 
barred link. 


, from a point in the last-mentioned rod beyond the fulcrum 
carried by the sectors attached to the reversing shaft. 

Ques. 514.—How is the forward or backward move¬ 
ment of the engine effected with the Joy valve-gear? 

Ans.—By inclining the sector on one or the other side 
of the center line of the reversing shaft and the point of 
cut-off and consequently the amount of expansion depends 
upon the amount of the inclination, the central position 
being mid-gear. The reversing arm moves these sectors 

















































196 


QUESTIONS AND ANSWERS 


to the required position. In large marine engines the 
reversing mechanism is operated by a small starting 
engine. On locomotives and small engines it is operated 
by hand. 

Ques. 515.—Mention one of the advantages possessed 
by the Joy valve-gear, over the double eccentric and link 
motion. 

Ans.—By this gear a constant lead is secured for all 
linked-up positions. 



Fig. 133. Stevenson Link Motion for Marine Engine. 


On the crank-shaft C there are keyed two eccentrics, one in the position to 
give ahead motion and the other in the position for astern motion. The eccentric 
rods are of equal length, and their ends are attached by working joints to the 
opposite ends of a curved link, E. 

f, 

Ques. 516.—Is the Joy valve-gear much in use? 

Ans.—It is applied to a large number of marine 
engines and locomotives. 

Ques. 517.—How is the lifting valve-gear of the 
marine beam engine actuated? 

Ans.—By curved cams keyed to a transverse shaft 
Fsur cams are fitted, two for steam and two for exhaust 














































TYPES OF ENGINES—CLASSIFICATION 


197 


Ques. 518. —How is the oscillating movement imparted 
to the transverse shaft? 


Ans.—From rocker-arms, one on each end of the 


I J M 



■0 



Fig. 134. 


The Marshall Valve-gear. The single eccentric, turning witr the crank, 
works the valve through a pivoted arm. The movement of the engine may be 
stopped or reversed by sliding the hand-lever on the notched quadrant, the 
loop paths show the movement of the valve rod-pin and also of the valve in 
vertical directions for ahead or backing motion. 





















198 QUESTIONS AND ANSWERS 



Fig. 135 shows an elevation and plan of the latest arrangement of Joy’s valve* 
gear applied to a vertical engine. In this gear eccentrics are dispensed with, and 
the movements of the slide-valve obtained from the connecting rod. The vibra¬ 
ting link B, jointed to the connecting rod at A, has one end constrained to move 
horizontally by the action of the radius rod C. One end of another rod, D, 
works on a pin in the vibrating link B; near the other end is a fulcrum carried 
by a pin F. attached to sliding blocks on each side working in sectors G, which 
are carried by the reversing shaft, the center line of the sector passing through 
the center of the reversing shaft. From D the motion is communicated to the 
























































































































TYPES OF ENGINES—CLASSIFICATION 


19') 


slide-valve rod by means of the link E, attached to a point K in the rod D beyond 
the fulcrum F. 

The forward or backward movement of the engine is governed by inclining, 
the sector on one or the other side of the horizontal center line, and the amount 
of expansion depends on the amount of the inclination, the exactly central or 
horizontal position being ‘mid-gear.’ The reversing arm F R moves these sectors 
to the required position, and its extremity R is connected to the starting engine 
H. The paths of the point A in the connecting rod, and also of the point B in 
the vibrating link, as the engine revolves, are indicated by dotted lines, as are 
also the extreme positions of the sector center lines for ahead and astern working 
respectively. The gear as drawn is in the stop position. By this gear a constant 
lead is secured for all linked-up positions, since when the piston is at the top or 
bottom of the stroke the pin F co-incides with the center of the reversing shaft, so 
that in this position any movement of the sectors does not affect the position of 
the slide-valve. The up and down motion of the point B therefore gives a 
constant movement of the valve equal to the lap plus the lead . while the 
horizontal motion sliding the block to and fro in the sectors adds the amount 
required for steam opening, this amount increasing with the angle of the sector 
to the horizontal. 


transverse shaft, the pins of which are engaged by hooks 
in the eccentric-rods. 

Ques. 519.—How are the poppet-valves of the West¬ 
ern river boat actuated? 

Arts.—By cams very similar to those on the beam 
engine. 

Ques. 520.—Describe the construction and action of 
a double-ported slide-valve. 

Ans.—A double-ported slide-valve acts in a manner 
similar to a single-ported valve in the admission of steam, 
but in addition there is what is practically an inner valve, 
to which steam is admitted through passages formed in 
the body of the valve. There are also two inner ^orts in 
addition to the two ports at the ends of the cylinder, and 
these inner ports or passages also lead to and are in con» 
nection with the end ports. 

Ques. 521.—What is the object in using a double- 
ported valve? 

Ans.—To reduce the travel of the valve, which in 
large engines would be too great with a single-ported 
valve. 



200 QUESTIONS AND ANSWERS 


Ques. 522 . —Are treble-ported valves used to any 
large ext int? 

Ans.—They are, on large marine engines, their action 
being on the same general principles as the double-ported 
slide-valve. 



Fig. 136. Joy’s Assistant Cylinder 

This consists of a small cylinder and steam-piston attached to the valve* 
spindle. The cylinder has a central inlet for steam. A, and two exhaust-ports, 
B, one for each end, leading to a common exhaust-pipe, and the piston is so 
constructed that by its motion the operations of steam admission, cut-off, release 
and compression are performed on each side of the piston. The apparatus is 
therefore, a small engine which exercises a force on the valve to move it up or 
down, and cushions steam at each end to absorb the momentum forces. These 
assistant cylinders give diagrams similar to that of an ordinary engines they 
exert from 15 to 25 I. H. P. each for the sizes fitted in marine engines, and the 
amount of power developed can be adjusted by means of a valve on the s + eam- 
pipe. If the main valve be linked in. the assistant cylinder is also automatically 
similarly affected. 9 



































































TYPES OF ENGINES-CLASSIFICATION 


201 


Ques. 523.—How is the pressure of the steam on the 
back of a large, flat slide-valve lessened and relieved? 
Ans.—By relief packing rings. 


Ques. 524.—How are 
relief packing rings fitted? 

Ans.—They are some¬ 
times fitted on the back of 
the valve, but are generally 
fitted on the valve-chest 
cover, and are pressed out 
by springs so as to work 
steam-tight on a planed 
surface, either on the back 
of the valve or, on the in¬ 
side of the cover, thus re¬ 
ducing the area on which 
the steam-pressure can act. 
The space inside the pack¬ 
ing ring is connected to the 
condensor or the receiver of 
the succeeding engine. 

Ques. 525.—Do relief 
rings work in a satisfac¬ 
tory manner? 

Ans.—They do not, as 
a general thing, being 
troublesome to make effi¬ 
cient, and they also are difficult of adjustment. 

Ques. 526.—What form of slide-valve has been found 
to give good satisfaction, especially on the high and inter¬ 
mediate cylinders of large marine engines? 



Fig, 137. Double-Ported Valve. 




































































202 


QUESTIONS AND ANSWERS 


Ans.—The piston slide-valve, consisting of two 
pistons connected together and working steam-tight in 
cylindrical chambers that contain the steam-ports. The 
face of each of the pistons corresponds to the face of the 
single-ported slide-valve, and performs the same functions. 

Ques 527.—What means are provided in large verti¬ 
cal engines for preventing the weight of the slide-valve, 
rod, and link gear from bearing upon the eccentric? 

Ans.—Balancing pistons, working in small steam- 
cylinders in the top end of the valve-casing. 

Ques. 528.—What is meant by setting the valve, or 
valves of an engine? 

Ans.—The adjustment and securing of the slide-valve 
in its proper position on the rod so as to secure the 
correct distribution of the steam in the cylinder. This 
also includes the fixing of the eccentric in its correct 
position on the shaft. 

Ques. 529.— What is the first, or one of the first, 

moves in valve-setting? 

Ans.—The rods and gear are first coupled together, 
and the crank is placed on the dead center. 

Ques. 530.—What is the meaning of the expression 
dead center? 

Ans.—An engine is on the dead center when the crank 
is in line with the piston-rod, that is, when the centers of 
the crank-shaft, crank-pin, and cross-head pin are exactly 
in line, so that the pressure of the steam on the piston 
exerts no turning moment on the shaft, but produces only 
direct thrust, subjecting the shaft to bending action only. 

Ques. 531.—With the engine on the dead center and 


TYPES OF ENGINES—CLASSIFICATION 203 

the rods and valve-gear all coupled up, what is the next 
move in valve-setting? 

Ans.—The slide-valve, by means of screws and nuts 
on the valve-rod, is fixed in the proper position to give 
the required lead for the corresponding end of the cylinder. 
The shaft is then turned around until the crank is on the 
opposite dead point and the lead of the valve for that 
end of the cylinder is measured. If the amounts of lead 
at the opposite ends are different, the position of the slide- 
valve on the rod should be adjusted by means of the nuts 
and screws, until the leads are either equal, or differ by 
the desired amount. The valve should then be perma¬ 
nently secured on the rod, so that its position may not 
alter. This is called equalizing the lead. 

Ques. 532.—If, after having gotten the lead equalized, 
it is found that there is too much or too little, how may 
it be decreased, or increased without altering the position 
of the valve on the rod? 

Ans.—To decrease the lead, reduce the angular 
advance of the eccentric, and to increase the lead it is 
necessary to increase the angular advance. 

Ques. 533.—What is the rule generally observed 
regarding the lead on large vertical engines? 

Ans.—In vertical engines, owing to the weight of the 
moving parts, the lead on the lower end is generally 
made slightly greater than the lead on the upper end, and 
more exhaust lap is allowed. In such cases the valve is 
set on the rod to give the required difference between the 
two leads. Then, if the lead be too great or too small at 
both ends, the required change may be made by moving 
the eccentric ahead or back on the shafts 





804 


QUESTIONS AND ANSWERS 



are fitted with isochronol or inertia governors, which 
control the position of the eccentric and vary the point 


Ques. 534.—Is the position of the eccentric on the 
ihaft necessarily fixed on all types of engines? 

Ans. —It is not. Many high-class stationary engines 


Fig. 138. Piston Vaeve. 







































































TYPES OF ENGINES-CLASSIFICATION 205 

of cut-off according as the load on the engine is light or 
heavy, thus maintaining a regular speed. 

Ques. 535.—What types of valves are used with 
isochronol governors? 

Ans.—Slide-valves of various patterns; box-valves, 
in which the steam passes through the valve; piston 
valves, in which the steam either passes through or 
around the ends of the valve. 

Ques. 536.—In all types of reciprocating engines the 
same factors affecting the distribution of the steam are 
present. What are they? 

Ans.—Outside lap, affecting admission and cut-off, 
and inside lap, affecting release and compression. 

Ques. 537.—How are these factors distributed in the 
four-valve type of engine? 

Ans.—They are distributed among the four valves, 
each valve performing its own particular function in the 
distribution of the steam for the end of the cylinder to 
which it is attached. 

Ques. 538.—What advantage is there connected with 
setting the valves of a four-valve engine, as compared 
with a single valve? 

Ans.—Each valve may be adjusted to a certain degree 
independently of the others, thus, for instance, the steam- 
valves of a Corliss engine may be adjusted to cut off the 
steam at any point from the beginning up to one-half the 
stroke, without in the least affecting the release or com¬ 
pression, because these latter events are controlled by the 
exhaust-valves. 

Ques. 539.—What is the first requisite in setting the 
valves of a Corliss engine 7 




206 


QUESTIONS AND ANSWERS 


Ans.—To place the crank on the dead center. 

Ques. 540.—What is the next move? 

Ans.—To adjust the length of the hook-rod, if it i 
adjustable; if not, then the length of the eccentric-roc' 
so that the wrist-plate will vibrate equal distances eac 



way from its central position, which is marked on top o: 
the hub. 

Ques. 541.—How should the rocker-arm, that carrie; 
the eccentric-rod, and hook-rod be adjusted? 

Ans.—The length of the eccentric-rod should be sucl 
































TYPES OF ENGINES-CLASSIFICATION 


207 


that the rocker-arm will vibrate equal distances each way 
from a vertical position. 

Ques. 542.—How may the vibration of the wrist-plato 
and rocker-arm be tested? 

Ans.—By connecting the eccentric-rod and the hook- 
rod in their proper places, and turning the loose eccentric 
around on the shaft in the direction the engine is to run. 

Ques. 543.—Having gotten these important adjust¬ 
ments correctly made, what is the next step in setting 

* 

Corliss valves? 

Ans.—Remove the back bonnets from the four valve 



chests, and while neither the working edges of the valves 
nor the ports can be seen, yet certain marks will be found 
on the ends of the valves and corresponding marks on the 
faces of the chests, which serve as a guide in setting the 
valves. 

Ques. 544.—Having removed the bonnets and found 
the marks, what is to be done next? 

Ans.—Temporarily secure the wrist-plate in its 
central position by tightening one of the set-screws on 
3 *Ke eccentric. Then connect the valve-rods to the wrist- 




















208 


QUESTIONS AND ANSWERS 


plate and to the small crank-arms attached to the ends of 
the valves, adjusting - their lengths so that the steam- 
valves will have from Y\ to t 9 6 inch lap, and the exhaust 
valves from to inch opening. 

Ques. 545.—In adjusting the steam-valves, what par" 
ticular detail should be carefully noted? 

Ans.—The direction in which the valves turn to open 
should be noted. In most Corliss engines the arm of the 
small crank to which the valve-rod is connected, extends 



Fig. 141. Exhaust-Vaeve of Coreiss Engine. 


downwards from the valve-stem. This will cause the 
valve to move towards the wrist-plate in opening. 

Ques. 546.—After the valve-rods have been properly 
adjusted as to length, what is the next move? 

Ans.—Place the engine on the dead center—either 
center will do—and move the eccentric around on the 
shaft in the direction 4he engine is to run, until the 
eccentric is far enough ahead of the crank to allow the 
steam-valve for that end of the cylinder the proper 
amount of lead opening, which will vary according to the 
size of the engine. Then tighten the eccentric set screws 























TYPES OP ENGINES- CLASSIFICATION 


209 


[j and trrn the engine around to the opposite center and 
•| note whether the lead is the same on both ends, 
t Ques. 547.—In case there is a difference in the lead 
for the two ends, how may it generally be equalized? 

Ans. By slightly altering the length of one of the 
valve-rods. 

Ques. 548. What is the next point to receive atten- 
e tion, in setting Corliss valves? 

s TABLE 8 

LAP AND LEAD OF CORLISS VALVES 


Size of Engine. 

Lap of Steam 
Valve. 

Lead Opening of 
Steam Valve. 

Lead Opening of 
Exhaust Valve. 

12 

14 

inches 

ll 

£ inch 

I 5 # 

A 

A 

inch 

A 

A 

inch 

ll 

16 

«1 

5 <1 

TT 

A 


A 

n 

18 

• 

I “ 

A 

<< 

A 

it 

20 


8 

A 

«« 

A 

«« 

22 

<1 

I “ 

A 

1C 

A 

<< 

24 


A 

A 

cc 

A 


26 

l • 

IS 

A 

*1 

A 

CC 

28 

It 

A “ 

A 

cc 

A 

f c 

30 

11 

\ 

A 

cc 

i 

«c 

32 

It 

\ “ 

A 

it 

B 

({ 

34 

• 1 

\ 

1 

cc 

| 

it 

36 

ll 

h “ 

J- 

«< 

& 

it 

38 

ll 

A 

* 

<« 

A 

CC 

40 

11 

A 

£ 

cc 

A 

cc 

42 

“ 

A 

s 

cc 

A 

cc 

Ans. — The 

adjustment of the 

lengths 

of the rods 


extending from the governor to the releasing mechanism > 
so that the valves will cut off at equal points in the 
stroke. 

Ques. 549.—How is this adjustment accomplished? 

Ans.—By raising the hook-rod clear of the wrist-plate 
pin and with the bar provided for the purpose, move the 
















210 


QUESTIONS AND ANSWERS 


wrist-plate to either one of its extreme positions, as 
shown by the marks on the hub, and, holding it in this 
position, adjust the length of the governor-rod for that 
steam-valve (which will then be wide open) so that the 
boss or roller which trips the releasing mechanism is just 
in contact, or within sV inch of it. Then move the wrist- 
plate to the other extreme of its travel and adjust the 
length of the other rod in the same manner. 

Ques. 550.—How may the accuracy of this adjust¬ 
ment be tested? 

Ans.—Raise the governor-balls to their medium 
position, or about where they would be when the engine 
is running at its normal speed, and block them there. 
Then having again connected the hook-rod to the wrist- 
plate, turn the engine around in the direction in which it 
is to run, and when the valve is released by the trip, 
measure the distance upon the guide that the cross-head 
has traveled from the end of the stroke. Now continue 
to turn the engine in the same direction until the other 
valve is released, and measure the distance that the cross¬ 
head has traveled from the opposite end of the stroke, 
and if these two distances are the same, the cut-off is 
equalized. If there is a difference, lengthen one rod and 
shorten the other until the point of cut-off is the same for 
both ends. The lengths of the dash-pot rods should also 
be adjusted, so that when the plunger is at the bottom of 
the dash-pot the valve-lever will engage the hook. The 
io*k-rmts on all rods should then be securely tightened, 




CHAPTER VII 

CONDENSERS—AIR-PUMPS—SEA-WATER 

Ques. 551.—What is the average composition of sea¬ 
water? 

Ans.—Sea-water contains about part of its weight 
of solid matter, of which common salt (sodic chloride) is 
the principle constituent. The average composition of 
the solid matter in sea-water may be taken as follows: 

Sodic chloride, or common salt .76 per cent 

Magnesic chloride..10 

Calcic sulphate, or gypsum. 5 

Magnesic sulphate. 6 

Carbonate of lime, and organic matter. 3 

Ques. 552.—Does the common salt in sea-water cause 
much trouble for the marine engineer? 

Ans.—It does not, for the reason that it remains 
soluble in water at all temperatures, and there is no 
deposit of salt, except under extreme circumstances. 

Ques. 553.—What is the principal scale-forming 
ingredient in sea-water? 

Ans.—Sulphate of lime, or calcic sulphate. Deposit 
is also formed by sulphate of magnesia, although it is less 
objectionable than the lime deposit. 

Ques. 554.—At what temperature does the sulphate 
of lime become insoluble in water and form a deposit on 
the boiler plates? 

Ans.—At a temperature of 280 degrees to 295 degrees 

211 











212 


QUESTIONS AND ANSWERS 


Fahrenheit, corresponding to a pressure of 35 to 
45 pounds pressure of steam by the gauge. As the tem¬ 
perature of the water rises, the other sulphates become 
insoluble, and at 350 degrees Fahrenheit, or 120 pounds 
gauge-pressure, sea-water is incapable of holding any j 
sulphates in solution. 

Ques. 555.—What other cause, besides a high tempera- 
ture, tends to precipitate these salts? 

Ans.—Increase of density, caused by evaporation of 
the water, even if the temperature remains about 
212 degrees Fahrenheit. Sulphate of calcium is thus 
deposited at a density of sV Common- salt does not 
crystallize out until a density of about is reached. 

Ques. 556.—When was it possible to use sea-water 
for feeding boilers? 

Ans.—In the early days of marine engineering, when 
a low-pressure (35 to 45 pounds) was carried, and the 
jet condenser was used, in which the steam was exhausted 
into the condensing chamber, where it came into actual 
contact with and was condensed by a jet of cold sea- 

water. The feed-water for the boilers was drawn from 

• 1 

this mixture of sca-water and condensed steam, conse¬ 
quently a large quantity of sea-water was sent into the 
boilers, but as the temperature was low and the density 
was not allowed to exceed 3the salts were held in 
solution fairly well. 

Ques. 557.—How was the increase of density pre¬ 
vented? 

Ans.—By blowing off a portion of the denser boiler- 
water at stated times, and making up the loss by ad- 







CONDENSERS-AIR-PUMPS-SEA-WATER 213 

mitting a larger quantity of salt water. This was termed 
“brining the boiler. ,, 

Ques. 558.—What led to the introduction of the 
surface condenser? 

| * Ans.—With the advent of high pressures, it was 

found impossible to prevent the deposit of scale, and all 
of its attendant evils. It was therefore found necessary 
to condense the exhaust steam without bringing it into 
actual contact with the condensing water, hence the sur¬ 
face condenser was designed. 

Ques. 559.—Mention two of the principal advantages 
gained by the use of the surface condenser. 

Ans.—First, by its use fresh feed-water is obtained 
for the boilers; second, the condition of the condensing 
water is of no importance, as regards the feed-water so 
that, no matter whether it is salt, muddy, acid, or other¬ 
wise impure, pure water is always obtained for the 
boilers, provided the condenser is maintained in good 
condition and no leakage is allowed to occur. 

Ques. 560.—What is the meaning of the word 
vacuum? 

Ans.—-That condition existing within a closed vessel 
during the absence of all pressure, including atmospheric 
pressure. 

Ques. 561.—How is a vacuum measured? 

Ans.—It is measured in inches of a column of mer¬ 
cury contained within a glass tube a little more than 
30 inches in height, having its lower end open and immersed 
in a small open vessel filled with mercury. The upper 
end of the glass tube is connected with the vessel in which 







214 


QUESTIONS AND ANSWERS 


the vacuum is to be produced. When no vacuum exists, 

the mercury will leave the tube and fill the lower vessel. 

* 

When a vacuum is maintained within the condenser, or 
other vessel, the mercury will rise in the glass tube to a 
height corresponding to the degree of vacuum. If the 
mercury rises to a height of 30 inches it indicates a per¬ 
fect vacuum, which means the absence of all pressure 
within the vessel, but this condition is never realized 
in practice, the nearest approach to it being about 
28 inches. 

Ques. 562.—Is the mercurial vacuum-gauge used in 
every-day practice? 

Ans.—For purposes of convenience it is not generally 
used, it having been replaced by the Bourdon Spring- 
gauge, although the mercury-gauge is used for testing. 

Ques. 563.—What is the advantage, from a purely 
economic standpoint, in allowing the exhaust steam to 
pass into a condenser in which a vacuum is maintained 
rather than to allow it to exhaust into the open air? 

Ans.—In a non-condensing engine, that is, an engine i 
in which the exhaust steam passes into the open air, the 1 
pressure of the atmosphere, amounting to 14.7 pounds 
per square inch at sea-level, is constantly in resistance to i 
the motion of the piston. Therefore the exhaust or ter- i 
minal pressure can not fall below the atmospheric pres- i 
sure and is generally from 2 to 5 pounds above it, caused : 
by the resistance of bends, and turns in the exhaust pipe, i 
or other causes which tend to retard the free passage of the 
steam. On the other hand, if the steam were allowed to 
exhaust into a condenser in which a vacuum of 25 inches I 


CO NDEN SERS AIR-PU M PS SEA-WATER 215 

is being maintained, the terminal pressure or back pres¬ 
sure in resistance to the forward motion of the piston 
would be but 2.5 pounds, and if a vacuum of 28 inches 
existed in the condenser there would be practically no 
back pressure, thus making available for useful work the 
14.7 pounds of steam which in the non-condensing engine 
was required to overcome the resistance of the atmos¬ 
pheric pressure. 

Ques. 564.—Is it proper, then, 
to consider the vacuum in a con¬ 
denser as power? 

Ans.—The vacuum can not be 
considered as power at all. It oc¬ 
cupies the anomalous position of 
increasing, by its presence, the ca¬ 
pacity of the engine for doing work. 

Ques. 565.—How is the vacuum 
in a condenser usually maintained? 

Ans.—By a pump called an air- 
pump, although a partial vacuum 
can be produced by the mere conden¬ 
sation of the exhaust steam as it enters the condenser, by 
allowing a spray of cold water to strike it. The steam when 
it first enters the condenser drives out the air and the vessel 
I is filled with steam at a low pressure, which^ when con¬ 
densed, occupies about 1,600 times less space than it did be¬ 
fore being condensed, hence a partial vacuum is produced. 
The action of the siphon injector is based upon this principle. 

Ques. 566.—Describe the construction and action of 
the siphon condenser. 



Fig. 142. 

Siphon Condenser. 































tl 6 


QUESTIONS AND ANSWERS 



BREAK. VACUUM 
SAFETY ATTACHMENT' 


INJECTION 

INLET 


Ans.—The siphon condenser is a form of jet condenser 
in which no air-pump is used. In this type of condenser 
the supply of condensing water is drawn from outside 
pressure, either from an overhead tank, or other source. 


EXHAUST 

INLET 




Fig. 143. Knowi.es Jet Condenser. 


and passing into an annular enlargement of the exhaust- 
pipe, is discharged downwards in the form of a cylindrical 
sheet of water, into a nozzle which gradually contracts. 
The exhaust steam, enterine at the same time, is con* 































































CONDENSERS-AIR-PUMPS-SEA-WATER 217 

; densed and the contracting neck of the cone-shaped nozzle 
gradually brings the water to a solid jet and it rushes 
through the nozzle with a velocity sufficient to create a 
vacuum. This type of condenser can only be used where 
the discharge pipe has a perfectly free outlet. 

Ques. 567.—Describe in general terms the construc¬ 
tion and action of the jet condenser. 

Ans.—The jet condenser is usually a vertical, cylindri- 





Fig. 144 . Sectional View of a Surface Condenser and Independent Air 

and Circulating Pumps. 


cal, cast-iron vessel, made air-tight, and which receives 
the exhaust steam from the low-pressure cylinder. In 
modern plants, condenser-shells are often made of sheet 
steel in cylindrical shape, reenforced with stiffening rings. 
The exhaust steam enters at the top and the condensing 
water enters usually at the side, flowing in through the 
spraying nozzle, and, discharging through a large num¬ 
ber of small holes, comes in contact with the steam in the 















































































218 


QUESTIONS AND ANSWERS 


form of spray, thus producing a quick condensation while 
falling to the bottom of the condenser, to be drawn off by 
the air-pump. A cock or valve is fitted in the injection 
pipe, for the purpose of regulating the supply of cooling 
water. 

Ques. 568.—Why is an air-pump a necessary part of a 
reliable jet-condensing apparatus? 

Ans.—The mixture of condensing water and con¬ 
densed steam must be pumped away constantly, also the 
condensing water always contains a certain volume oi 
air in solution, which may be liberated, either by boiling 
it or by reducing the pressure to which it is subjected 
This air is liberated in the condenser, and if it is noi 
pumped away regularly, it is liable to accumulate anc 
spoil the vacuum. 

Ques. 569.—How may the dimensions of a single-act 
ing air-pump for a given sized engine be determined? 

Ans.—In the solution of this problem, two factor; 
must be considered: First, the total volume of the low 
pressure cylinder; second, the density of the exhaus 
steam. The volume of the air-pump cylinder is thei 
found by the following rule: Multiply the volume of th< 
low-pressure cylinder in cubic feet by 3.5, and divide thi ) 
product by the number of cubic feet contained in 1 pourn [ 
weight of exhaust steam at the pressure at which i< 
enters the condenser. This rule applies only to jet con j 
densers. i 

j 

Ques. 570.—Describe the construction and action o t 
the surface condenser. i 

Ans.—The surface condenser, like the jet condenser ( 


w 







CONDENSERS—AIR-PU M PS—SEA-WATER 


219 


s an air-tight iron or steel vessel, either cylindrical or 
ectangular in shape, but, unlike the jet condenser, it is 


itted with a large number of brass or copper tubes of 
mall diameter (generally about % inches), through which 
:old water is forced by a pump called a circulating 



Fig. 145. 

Side view of large cylindrical horizontal surface-condenser having two 
xhaust-inlets. The tubes are not shown. The steam enters at the orifices marked 
and is withdrawn, when condensed, through the orifice B by the air-pump. 
Tie circulating water enters at C, and is confined by the diaphragm D to the 
ower half of the tubes, and, having traversed these tubes, it returns through the 
ipper half of the tubes, being finally discharged to the sea through the pipe E- 
\ T. are the tube plates near the ends of the condenser casing. 

jump. A vacuum is maintained in the body of the con- 
lenser by the air-pump, and the steam exhausting into 
his vacuum is condensed by coming in contact with the 
:ool surface of the tubes. Or, as is often the case, the 
ixhaust steam passes through the tubes instead of around 



































































220 


QUESTIONS AND ANSWERS 


them, and the cooling water is forced into and through 
the body of the condenser, the vacuum in this case being 
maintained in the tubes. The tubes may be placed either 
vertical or horizontal. When the steam is passed through 
the tubes, they are generally placed vertical, while, on the 



C/fiCuiArm Mre* 

/ttl£T 


Eic. 146. End Sectional View oe Cylindrical Horizontal SubEaCE 

Condenser, Showing a Portion of the Tubes. 


other hand, if the water circulates through them they ar< 
placed horizontal. The system of causing the water t< 
circulate through the tubes, the steam surrounding them 
is the more general. 







































CONDENSERS-AIR-PUMPS-SEA-WATER 221 

Ques. 571. How are the tubes generally arranged in 
i surface condenser? 

Ans. They are arranged in one or more systems, so 
hat the condensing water passes through the condenser, 
isually twice, the coldest water entering at the bottom 
nd coming in contact with the steam at its lowest tem- 
•erature, and the warmest water at the top meeting the 

hottest steam. The exhaust 
steam enters at the top and 
after passing over the cold 
tubes is removed in the form 
of water, by the air-pump. 
The steam is directed in its 
downward course by baffle- 
plates, thus securing complete 
utilization of the cooling sur¬ 
face. A space is provided at 
the bottom of the condenser 
for the accumulation of the 
water of condensation below 
the cooling surface. The con¬ 
denser casing or shell for naval 
2 ssels is either cast in brass or else built up from com- 
osition sheets, in order to save weight and prevent cor- 
)sion and galvanic action, which would be more liable 
> take place with an iron or steel shell, 
i Ques. 572.—How are the tuLes secured in their places? 

Ans.—Brass or composition tube-plates are placed in 
le shell, near each end, sufficient space beine' left 
*tween the outside cover-plates and the tube-plates iu» 



g. 147. Details oe Wick and 
Gland Packing for the Tubes 
of a Surface Condenser. 































222 


QUESTIONS AND ANSWERS 


the circulation of the cooling water. Into these plates 
which are thick enough to furnish a good bearing for tin 
tubes, the ends of the tubes are fitted and packed thor 
oughly tight, sometimes with a wood packing, sometime] 
with small screwed stuffing boxes with glands and fob 
lowers, which tighten upon wick packing. The woo<i; 
packing consists of a small soft wooden sleeve, which ijj 
forced into the small hole over the tube end in a drj 
state, and after becoming wet it swells and clamps th 

a. 


Fig. 148. Method of Packing Tubes of a Worthington Surface Condense 

One end of each tube is flanged and rigidly held in the tube head by meai 
of a screw follower; the other end of the tube passes through an adjustab; 
gland, which permits of free movement of the tube during expansion ar|, 
contraction. This method of securing rigidly one end of the tube reduces tl 
number of glands or stuffing-boxes to just one-half the number found in ordi: 
ary condensers. The glands can be readily removed and the packing replace 
if it becomes leaky from long use. j, 

tube, thus forming and preserving a tight joint so Ion 
as it is kept wet. 

Ques. 573.—Which kind of packing is the most reli; 
able for condenser tubes? 

Ans.—The gland and wick, for the reason, that 
always remains tight, while on the other hand the woo 
packing will shrink and become loose if the condenser i 
out of service for a time. . 




























CONDENSERS AIR-PUMPS SEA-WATER 223 

Ques. 574.—What are the usual dimensions of the 
ubes of surface condensers? 

Ans.—They are generally about Y inches in diameter, 
re made of brass, about sV of an inch thick, of a com- 
osition consisting of not less than 70 per cent of coppei 
ad not less than 1 per cent of tin, the remainder being 
inc, the small quantity of tin being added to prevent 
alvanic action. The tubes are pitched not less than f J 



G. 149. Worthington Surface Condenser, with Air and Circulatin« 

Pump. 

ches apart in order to allow sufficient material for the 
and. They are zigzagged so as to occupy as small a 
)lume as possible. Condenser tubes vary considerably 
length, depending upon the size of the condenser, the 
suai length in large condensers being from 8 to 10 feet, 
hile in some very large condensers the tubes are 14 or 
> feet in length. The tube-plates are about 1 inch thick, 
order to provide sufficient depth for the gland and 
icking for the tubes. 








224 


QUESTIONS AND ANSWERS 


Ques. 575.—What type of air-pump is generally used 
Ans.—The vertical single-acting air-pump has bee 



Fig. 150. 

SccUon of Blake independent air-pump, fitted in many vessels, includir 
several U. S. warships. There are two steam-cylinders and two sinele actir 
vertical air-pumps of the usual type. It works at slow speed and eives ex-e 
lent results. 



































































































































CONDENSERS-AIR-PUMPS-SEA-WATER 


225 


found to be the most efficient. In vertical engines the air- 
pump generally receives its motion from the cross¬ 
head of the engine, through the medium of a short 
walking-beam. There are, however, a great many 
engines fitted up with an independent air-pump and 
condenser, in which the air-pump is simply an ordinary 
double-acting steam-pump, having its own steam- 
cylinder, and may be operated independently of the engine, 
which is a great advantage, as there is not so much 
danger of the water from the condenser backing up into 
the cylinder in case of a sudden shut-down of the engine, 
which is liable to occur with a jet condenser. 

Ques. 576.—Describe the parts of the vertical single- 
acting air-pump. 

Ans.—It consists of the barrel, or cylinder, the suc¬ 
tion-channel way at the bottom, the cover, with delivery- 
channel way and the hot well, the whole being made air¬ 
tight. The moving parts are the bucket, or piston, with 
its valves, the foot-valves and the head-valves. 

Ques. 577.—Describe the arrangement of the air- 
pump in connection with the condenser. 

Ans.—The suction-channel way is in connection with 
the lowest part of the condenser, in order that the water 
can be readily and completely removed from the condenser. 
It usually supports the foot-valves and all joints and| 
valve-seat division-plates require to be fitted air-tight. 
The barrel is generally connected to a flange or facing of 
the suction-channel way, and it is constructed of com¬ 
position or cast iron with a composition sleeve pressed in 
and bored out truly cylindrical, in order to form a jmooth 







226 


QUESTIONS AND ANSWElS 


and durable working-cylinder £qt the buckc pistor 
which is kept tight against the barrel, either by watei 



Fig. 151. Sectional View oe Vertical Single Acting Air-pump. 


grooves, or, more commonly, by packing, consisting < 
.tfie more split metallic packing rings. Sometim. 
































































CONDENSERS-AIR-PUM PS-SEA-WATER 


227 


fibrous soft packing, held in place and compressed by a 
follower ring, is used. A stuffing box is provided in the 
top cover, through which the piston-rod or trunk, as the 
case may be, has water-tight passage. 

Ques. o l 8. What kind of valves are used in air- 
pumps? 



\ 

Fig. 152. 

Details op Rubber Valve, Valve- 
seat and Guard for Air-pump. 


Ans.—Rubber valves, 
either of hard or soft rub¬ 
ber, but since the introduc¬ 
tion of mineral oil as a 
lubricant for the engine cyl¬ 
inders, it has been found 
that the ordinary rubber 
valves deteriorate under its 
influence, and metal valves 
are now largely coming into 
use, especially in the navies. 
They may be made of thin 
sheet metal, are light, and 
not affected by grease, if 
cleaned occasionally, and 
will last a long time. In 
form, air-pump valves are 
either single rectangular 


flaps that lift on one edge 
against a curved metallic guard, or else there are a number 
:>f smaller circular valves, lifting bodily from their seats, 
and secured to the seat by a central stud, which also carries 

t i metal guard above the valve. The valve-seats are usually 
ndependent, being constructed of composition metal, and 










































228 


QUESTIONS AND ANSWERS 


pressed into their places. They are divided into small 
spaces by gratings, so that the unsupported area of the 
valve may not be too large. The bucket carries the 
bucket-valves, which allow the air and water to pass 
through to the delivery side. Air-pump valves are some¬ 
times fitted with spiral springs of bronze wire on top, to 
secure quick closing. The flap valves are clamped to the 
seat, on the stationary edge, by their curved guards. 

Ques. 579.—How is the bucket or piston of the air- 
pump actuated? 



Ans.—Either by a solid piston-rod, or by a hollow 
trunk, made entirely of composition, or covered by a 
composition sleeve. With the piston-rod type it is neces¬ 
sary to have a connecting rod and guides above the top 
cover of the air-pump, while the trunk type contains the 
connecting rod bearing in the trunk, near the bucket, and 
requires no extra guides. 

4 Ques. 580.—What is the function of the hot well? 

Ans.—It acts as a small reservoir, for the accumula¬ 
tion of the discharge-water from which the feed-pumps 






































CONDENSERS-AIR-PUMPS-SEA-WATER 


229 


draw their supply. The later vessels in the English navy 
are fitted with feed-tanks" in which the discharge from 
the air-pumps is allowed to accumulate, and from which 
the feed-pumps draw their supply of water for feeding 
the boilers. There is a feed-tank for each engine-room } 



; Fig. 154. Worthington Central Condenser for a Large Stationary Plant, 

Showing Pumps and Piping. 

I ' 

and they are connected by a pipe running between the two 
! engine-rooms, fitted with a shut-off valve worked from 
either engine-room. These feed-tanks are fitted with 
glass water-gauges and zinc slabs. 


















































































230 


QUESTIONS AND ANSWERS 


Ques. 581.—What is the function of the circulating 
pump in connection with the surface condenser? 




Fi» -155. Transverse Section op a Centrifugal Pump. B, Casing. D D 

Curved Vanes. * * 


Ans. It either forces or draws the cooling watei 
through the tubes or the body of the condenser. 






































CONDENSERS-AIR-PUMPS-SEA-WATER ^31 

Ques. 582.—What type of pump has beeu icund to be 
best adapted to this work? 

Ans.—The centrifugal pump worked by an indepen¬ 
dent auxiliary engine, for the reason that the pump works 
smoothly, there are no valves, and having a separate 
engine, it can be kept working and the condensers kept 
cool when the main engines are stopped, which is not the 
case with a pump that receives its motion from the main 
engines. Another great advantage possessed by the 
independent system is, that the speed may be regulated 
so as to supply the required quantity of water. 

Ques. 583.—Describe the construction and action of 
the centrifugal circulating pump. 

Ans.—The pump consists of an impeller wheel or fan 
revolving inside a casing. The impeller and casing are 
made of gun metal, and the spindle or shaft carrying the 
impeller is either cast of gun metal in one piece with the 
impeller, or formed separately of forged bronze and keyed 
to it. This spindle runs in lignum-vitae bearings and is 
lubricated with water. The impeller generally consists 
of a central web guiding the incoming'water, with two 
side-plates that gradually approach each other as they 
near the circumference and between which runs a series 
of curved vanes. These vanes are curved away from the 
direction of rotation as they proceed from the boss to the 
circumference. The water enters the central part of the 
impeller through the inlet pipe and is thrown by the 
rapidly revolving vanes outwards and around into the 
casing which surrounds the circumference of the wheel, 
The casing is of gradually increasing area and leads to 


232 


QUESTIONS AND ANSWERS 


the delivery pipe, through which it is forced by the cen 
trifugal action to the condenser, where, after traversing 
the tubes, it is discharged overboard. The casing is 



Fig. 156. Longitudinal Section of a Centrifugal Pump. A, Central Wei 
C C, Side Plates. E, Inlet. F, Discharge. 


formed in two parts to enable the impeller to be insertec 
and also to facilitate insoection. 



































































































CONDEN SERS-AIR-PU M PS-SEA-WATER 


233 


Ques. 584. How is the quantity of water required to 
condense the exhaust steam of an engine determined? 

Ans.—The quantity of cooling water required for a 
condensing system depends primarily upon the system, 
whether it is surface condensing or whether the condenser 
is a jet condenser. The surface condenser needs a greater 
quantity of water than does the jet condenser. This is 
due to the fact that in the surface condenser the water, 
not being mixed with the steam, can not absorb the heat 
so rapidly. 

Ques. 585.—About how much more water does a sur¬ 
face condenser require than is needed by a jet condenser? 

Ans.—About 15 per cent more. 

Ques. 586.—What three factors determine the quantity 
of cooling water required? 

Ans.—First, the density, temperature, and volume of 
the steam to be condensed in a given time; second, the 
temperature of the overflow and third, the temperature of 
the injection water. For instance, it may be desired to 
keep the overflow at as high a temperature as possible, for 
the purpose of feeding the boilers, or the temperature of 
the injection or cooling water varies greatly. It may 
be 35 degrees in the winter and 70 degrees in the summer. 
In the marine service the temperature of sea-water 
varies considerably, depending upon the locality, in the 
tropics the temperature of the sea-water in the summer 
being often as high as 85 degrees Fahrenheit. 

Ques. 587.—What quantity of condensing water would 
be required in a jet condenser into which the exhaust 
steam under an absolute pressure of 7 pounds is passing. 






234 


QUESTIONS AND ANSWERS 


assuming the temperature of the cooling water to be 
55 degrees and the temperature of the overflow to be 
110 degrees? 

Ans.—In these calculations the total heat in the steam 
must be considered. This means not only the sensible 
heat, but the latent heat also. Now in 1 pound weight of 
steam at 7 pounds absolute pressure the total heat is 
1,135.9 heat units. The temperature of the overflow being 
110 degrees, the total heat to be absorbed from each pound 
weight of steam in this case would be 1,135.9 
— 110 = 1025.9 thermal units. The temperature of the 
condensing water being 55 degrees and the temperature 
of the overflow being 110 degrees, there will be 110 
degrees—55 degrees = 55 degrees of heat absorbed by 
each pound of cooling water passing into and through the 
condenser, and the number of pounds of water required 
to condense each pound weight of steam under these 
conditions will equal the number of times 55 is con¬ 
tained in 1,025.9, thus, 18.65 pounds. Assuming 

the steam consumption of the engine to be 17 pounds per 
indicated horse-power per hour, then 17 X 18.65 = 317.05 
pounds of water is required per horse-power per hour for 
condensing purposes. < 

Ques. 588.—How is the weight of cooling water 
required per hour determined, when the steam consumption 
per indicated horse-power per hour is not known? 

Ans.—In this case the volume of steam exhausted per 
hour must be considered. Thus, assume the cylinder from 
which the steam is exhausted to be 24 X 48 inches and 
the revolutions per minute to be 80. The piston dis- 


235 


CONDENSERS-AIR-PUMPS-SEA-WATER 

3 placement will equal area of piston less one-half area of 
5 od, multiplied by length of stroke. The area of a circle 
54 inches in diameter = 452.39 square inches. Suppose 
3 piston-rod to be 4.5 inches in diameter, its area is 
3.5.904 square inches, one-half of which = 7.952 square 

Table No. 9 
s 

Jet Condensing 

5 Quantity of Injection Water per Revolution of Engine. 


INJECTION WATER 50° OVERFLOW 110° 


Low-pressure Cylinder. 

Single-cylin¬ 
der, Water 
per Rev. 

Two-cylinder, 
Water per 
Rev. 

Three-cylin¬ 
der, Water 
per Rev. 

Lbs. 

Galls. 

Lbs. 

Galls. 

Lbs. 

Galls. 

20x36 inches. 

4.2 

.5 

3.9 

.47 

3.6 

.43 

22x36 “ . 

5.1 

.61 

4.8 

.57 

4.4 

.53 

24x42 “ . 

7. 

.84 

6.6 

.79 

6. 

.72 

26x42 “ . 

8.3 

1. 

7.8 

.93 

7.2 

.87 

28x48 “ . 

11. 

1.45 

10.4 

1.24 

9.5 

1.14 

30x48 “ . 

12.6 

1.52 

11.7 

1.41 

10.8 

1.3 

32x54 “ . 

16.2 

1.95 

15. 

1.81 

13.9 

1.68 

34x54 “ . 

18.3 

2.2 

17.0 

2.05 

15.8 

1.9 

36x60 “ . 

22.8 

2.75 

21.2 

2.55 

19.6 

2.36 

38x60 “ . 

25.5 

3.07 

23.7 

2.85 

21.9 

2.64 

40x66 “ . 

31. 

3 73 

28.8 

3.45 

26.7 

3.2 

44x66 “ . 

37.5 

4.51 

34.8 

4.2 

32.2 

3.8 

48x72 “ . 

48.5 

5.84 

45. 

5.42 

41.7 

5. 

52x72 “ . 

57. 

6.89 

53.1 

6.4 

49.2 

5.9 

56x72 “ . 

66. 

7.9 

61.5 

7.41 

57. 

6.8 

60x72 “ . 

75.6 

9. 

70.5 

8.5 

65.3 

7.8 

64x72 “ . 

85. 

10. 

80. 

9.6 

74. 

8.9 


(Table No. 9.—From Book on Compound Engines. By James Tribe, De* 
oit, Mich. ) 


iches. The effective area of the piston is therefore 
52.39 — 7.952 = 444.4 square inches and the piston 
isplacement equals 444.4 X 48 = 21,332.64 cubic inches, 
t is necessary in this calculation to express the total 
olume of steam exhausted per minute in cubic feet, 
iierefore 21.332.64 -?■ 1.728 (number of cubic inchessin a 


















































236 


QUESTIONS AND ANSWERS 


cubic foot) gives 12.34 cubic feet of piston displacement 
and the engine running at a speed of 80 revolutions pei 
minute will send into the condenser a volume of stean 
equal to twice the piston displacement multiplied by th< 
number of revolutions per minute, expressed thus: 12.3^ 
X 2 X 80 = 1,974.4 cubic feet per minute. Assuming th< 
absolute pressure of the exhaust to be 7 pounds pe 
square inch, the weight of 1 cubic foot of steam at 
pounds absolute is .0189 pounds and the total weight o 
steam exhausted per minute would be 1,974.4 X .0189 = 
37.3 pounds, and if 18.65 pounds of water is required t 
condense 1 pound weight of steam at 7 pounds absolute 
the total weight of water required per minute in this cas 
would be expressed as follows: 37.3 X 18.65 = 695. 
pounds, or per hour 695.8 X 60 = 41,748 pounds, equal t 
5,029 gallons. 

Ques. 589.—What quantity of condensing water woul 
be required in a surface condenser, assuming the cond: 
tions to be the same as described in the answer to questio 
587? 

Ans.—A surface condenser requires about 15 t 
20 per cent more condensing water than a jet condenst 
does. It was seen in the answer referred to that 18.(< 
pounds of water were required to condense 1 pour 
weight of steam, therefore the quantity of water requin 
by the surface condenser would be about 22 or 23 poun< 
for each pound of steam. 

Ques. 590.—What provision is made on board • 
vessels for obtaining a supply of water for the condense 
and for other purposes? 


CONDENSERS-AIR-PUMPS-SEA-WATER 


2S7 


Table io 

Areas and Circumferences of Circles. 


Diam. 

Area. 

Circum. 

Diam. 

Area. 

Circum. 

Diam 

Area. 

1 ircutn. 

•25 

.049 

.7854 

15.5 

1SS.692 

48.694 

31 

754.769 

97.389 

• 5 

.1963 

1.5708 

16 

201.062 

50.265 

31-25 

766.992 

98.175 

1.0 

.7854 

3.1416 

16.25 

207.394 

51.051 

31.5 

799.313 

98.968 

1.25 

I.2271 

3.9270 

16.5 

213.825 

51.836 

32 

804.249 

100.53 

i-5 

1.7671 

4.7124 

17 

226.980 

53 407 

32.25 

816.86 

101.31 

2 

3.1416 

6.2832 

17-25 

233.705 

54.I92 

33 

855.30 

103.67 

2.25 

3.9760 

7.0686 

17.5 

240.520 

54-978 

33.25 

868.30 

104.45 

2.5 

4.9087 

7.8540 

18 

254-469 

56.548 

33-5 

881.41 

105.24 

S3 

7.0686 

g.4248 

18.25 

261.587 

57-334 

34 

907.92 

106.81 

3-25 

8.2957 

10.210 

18.5 

268.803 

58.119 

34.25 

921,32 

107.60 

1 3' 5 

9.6211 

IO.995 

19 

283-529 

59-690 

34-5 

934.82 

108.38 

J 4 

12. 566 

12.566 

19-25 

29I.039 

60.475 

35 

962.il 

106.95 

] 4-25 

14. lS6 

13.351 

19-5 

298.648 

61.261 

35.25 

975.90 

no. 74 

4-5 

I5.9 0 4 

14.137 

20 

314.160 

62.832 

35-5 

989.80 

hi.52 

5 

19-635 

I5-708 

20.25 

322.063 

63.617 

36 

1017.8 

113.09 

5.25 

21.647 

16.493 

20.5 

330.064 

64.402 

36.25 

1032.06 

113-88 

J 5 ' 5 

2 L758 

17.278 

21 

346.361 

65.973 

36.5 

1046.35 

114.66 

6 

28.274 

18.849 

21.25 

354-657 

66.759 

37 

1075.21 

116.23 

6.25 

30.679 

I9-635 

21.5 

363.051 

67.544 

37.25 

1089.79 

117.01 

4 6.5 

33-I83 

20.420 

22 

380.133 

69.115 

37.5 

1104.46 

117.81 

1 7 

38.4S4 

21.991 

22.25 

388.822 

69.900 

38 

1134-II 

119.38 

7.2 =■ 

41.232 

22.776 

22.5 

397.608 

70.686 

38.25 

II49.0S 

120.16 

1 7 - 5 

44- i 73 

23.562 

23 

415.476 

72.256 

38.5 

1164.15 

120.95 

8 

50.265 

25.132 

23.25 

424-557 

73.042 

39 

1 £94.59 

1:2.52 

i 8.25 

53.456 

25.9 l8 

23.5 

433.731 

73.827 

39-25 

1209.95 

123.30 

8.5 

56.745 

26.703 

24 

452.390 

75.398 

39.5 

1225.42 

124.09 

9 

63.617 

28.274 

24.25 

461. 864 

76.183 

40 

1256.64 

T2 5.66 

Q. 2 r 

67.200 

29.059 

24.5 

471.436 

76.969 

40.25 

1272.39 

126.44 

9 5 

70.882 

29.845 

25 

490.875 

78.540 

40.5 

1288.25 

127.23 

flO 

78.540 

31.416 

25.25 

500.741 

79.325 

4i 

1320.25 

128. So 

10.2' 

82.516 

32.201 

25-5 

510.706 

80.110 

41.25 

1336.40 

129.59 

eio.5 

86.590 

32.986 

26 

530-930 

81.681 

41.5 

1352.65 

130.37 

[I 

95-033 

34-557 

26.25 

541.189 

82.467 

42 

I385-44 

I3I-94 

(yn.25 

99.402 

35-343 

26.5 

551.547 

83.252 

42.25 

1401.98 

132.73 

ti. 5 

10-3.869 

36.128 

27 

572.556 

84.823 

42.5 

1418.62 

I33.5I 

n i2 

113.097 

37.699 

27.25 

583.208 

8 5.60S 

43 

1452.20 

135.08 

,12.25 

117.859 

38.484 

27.5 

593.958 

86.394 

43-25 

1469.13 

135.87 

l 

12 .5 

122.718 

39.270 

28 

615.753 

87.964 

43-5 

1486.17 

136.65 

djc 3 

132.732 

40.840 

28.25 

626.798 

88.750 

44 

1520 53 

138.23 

13-25 

137.8S6 

41.626 

28.5 

637.941 

89-535 

44-25 

1537.86 

139.01 

[3-5 

143.130 

42.411 

29 

660. 521 

91.106 

44-5 

1555.28 

139.80 

14 

I53-938 

43.982 

29-25 

671.958 

91.891 

45 

I590-43 

£41.37 

( 14.25 

I59-485 

44- 767 

29-5 

683.494 

92.677 

45-25 

1608.15 

142.15 

„£4.5 

165.130 

45-553 

30 

706.860 

94.248 

45-5 

1625.97 

142.94 

£5 

176.715 

47.124 

30.25 

718.690 

95.033 

46 

1661.90 

I44.5I 

£5 25 

182.654 

4 7- 909 

30.5 

730.618 

95.818 

46.25 

1680.01 

145.29 





























238 


QUESTIONS AND ANSWERS 


Table \o—Continued. 


Diam. 

Area. 

Circum. 

Diam. 

/ rea. 

Circum. 

Diam. 

Area. 

Circum 

46.5 

1698.23 

146.08 

62.25 

3043.47 

195.56 

78 

4778.37 

245.04 

47 

1734.94 

147.65 

62.5 

3067.96 

196.35 

7S.25 

4809.05 

245.83 

47-25 

i 753->5 

148.44 

63 

3117.25 

197.92 

78.5 

4839.83 

246.61 

47-5 

1772.05 

I49. 22 

63.25 

3142.04 

198.71 

79 

4901.68 

248.19 

48 

1809.56 

150.79 

63.5 

3166.92 

199.50 

79- 2 5 

4932.75 

248.97 

48.25 

1828.46 

151.58 

64 

3216.99 

201.06 

79-5 

4963.92 

249. 76 

43.5 

1847.45 

152.36 

64.25 

3242.17 

201.85 

80 

5026.56 

25 L 33 

49 

1SS5.74 

153-93 

64.5 

3267.46 

202.68 

80.5 

5089.58 

252.90 

49-25 

1905.03 

154-72 

65 

3318.31 

204.20 

81 

5153.00 

254-47 

49-5 

1924.42 

155-50 

65.25 

3343-88 

204.99 

81.5 

5216.S2 

256.04 

50 

1963.50 

157.08 

65.5 

3369.56 

205.77 

82 

5281.02 

257.61 

50-25 

1983.18 

157.86 

66 

3421.20 

207.34 

82.5 

5345-62 

259.18 

50.5 

2002.96 

158.65 

66.25 

3447.16 

20S. 13 

83 

5410.62 

260. 75 

5 i 

2042.82 

160.22 

66.5 

3473.23 

208.91 

83.5 

5476.OO 

262.32 

51-25 

2062.90 

161.00 

67 

3525.66 

210.49 

84 

5541.78 

263 89 

5 L 5 

2083.07 

161.79 

67-25 

3552.01 

211.27 

84.5 

5607.95 

265.46 

52 

2123.72 

163.36 

67-5 

3573.47 

212.06 

85 

5674.51 

267.04 

52.25 

2144.19 

164.14 

68 

3631.68 

213.63 

85.5 

5741-47 

268.60 

52.5 

2164.75 

164.19 

68.25 

3658.44 

214.41 

86 

5808.81 

270.17 

53 

2206.18 

166.50 

68.5 

3685.29 

215.20 

86.5 

5876.55 

27 L 75 

53-25 

2227.05 

167.29 

69 

3739.28 

216.77 

87 

5944*66 

273.32 

53-5 

2248.01 

168.07 

69.25 

3766.43 

217.55 

87.5 

6013.21 

274.89 

54 

2290.22 

169.64 

69.5 

3793-67 

218.34 

88 

6082.13 

276.46 

54-25 

2311.48 

170.43 

70 

3S48.46 

219.91 

88.5 

6151.44 

278.03 

54-5 

2332.83 

171.21 

70.25 

3875-99 

220.70 

89 

6221.15 

279.60 

55 

2375.83 

172.78 

70.5 

3903.63 

221.48 

89-5 

6291.25 

281.17 

55-25 

2397.48 

173-57 

7 i 

3959-20 

223.05 

90 

6371.64 

282.74 

55-5 

2419.22 

174.35 

71.25 

3987.13 

223.84 

90.5 

6432.62 

284.31 

56 

2463.01 

175.92 

71.5 

4015.16 

224.62 

9 i 

6503.89 

285.88 

56.25 

2485-05 

176.71 

72 

4071.51 

226.19 

91.5 

6573.56 

287.46 

56.5 

2507.19 

177-5 

72.25 

4099.83 

226.9S 

92 

6647.62 

289.03 

57 

2551.76 

179.07 

72.5 

4128.25 

227.75 

92.5 

6720.07 

290.60 

57-25 

2574.19 

179.85 

73 

4135.39 

229.34 

93 

6792.92 

292.1; 

57-5 

2596.72 

180.64 

73.25 

4214.11 

230.12 

93-5 

6866.16 

293.74 

58 

2642.oS 

182.21 

73-5 

4242.92 

230.91 

94 

6939.79 

295-31 

58-25 

2664.91 

182.99 

74 

4300.85 

232.48 

91-5 

7013.81 

296.88 

53.5 

2687.83 

183.78 

74-26 

4329.95 

233.26 

95 

7088.23 

298.45 

59 

2733-97 

185.35 

74.5 

4359-16 

234.05 

95-5 

7163.04 

300.02 

59-25 

2757.19 

186.14 

75 

4417.87 

235.62 

96 

7238.25 

301.59 

59-5 

2780.51 

186.92 

75.25 

4447-37 

236.40 

96.5 

7313.80 

303.16 

60 

2827.44 

188.49 

75-5 

44/6.97 

237.19 

97 

7389.81 

304.73 

60 25 

2851.05 

189.28 

76 

4536.37 

238.76 

97-5 

7466.22 

306.30 

60.5 

2874.76 

190.06 

>.25 

4566.36 

239.55 

98 

7542.89 

307.88 

61 

2922.47 

191.64 

76.5 

4596.35 

240.33 

98.5 

7620.09 

309.44 

61.25 

2946.47 

192.42 

77 

4656.63 

241.90 

99 

7697.70 

311.02 

61.5 

2970.57 

193.21 

77 25 

4686.92 

^242.69 

99-5 

7775.63 

312.58 

62 

3019.07 

194.78 

77-5 

4717.30 

243.47 

100 

7854.00 

314.16 
































CONDENSERS-AIR-PUMPS-SEA-WATER 


239 


Ans.—All holes in the hull of a ship below the water¬ 
line for the supply or discharge of condensing wa- 
5 ter, or for any other purpose, are fitted with valves 
having long spindles 
which are brought inside 
the ves-sel through stuff¬ 
ing boxes, in order that 
the valves may be worked 
from inboard. The cir¬ 
culating pumps take 
their suction from a 
large screw-down inlet 
valve on the bottom of 
the ship, while the dis¬ 
charge is through simi¬ 
lar valves on the ship’s 
side. 

Ques. 591.—W hat 
type of valve is largely 
used for this purpose? 

Ans.—The Kingston 
sea-valve. Strainers are 
placed over all inlets, to 
prevent the entrance of 
)2 weeds and other impuri- 
ties* 



Fig. 157. Sea-valve. 












































































CHAPTER VIII 


AUXILIARY MACHINERY AND FITTINGS 

Oues. 592.—Besides the air and circulating pumps, 
what other pumps are required in well-equipped steam 
plants, or aboard steam-ships? 

Ans.—Boiler feed-pumps, fire service, pumps for 
hydraulic elevators, and other service requiring water- 
pressure, and in addition, on ship-board, pumps are 
required for emptying the bilges and tanks and for supply¬ 
ing water for washing the decks, evaporator service and 
for sanitary purposes. 

Ques. 593.—Is there a special pump provided for each 
service? 

Ans.—Not in all cases, but one pump may be con¬ 
nected in such a manner as will permit of its being used 
alternately for several different purposes. However, a 
special pump is, or at least should always be provided for 
feeding the boilers. Also a special bilge-pump is usually 
supplied, for the reason that it handles very dirty water, 
that should not be passed through any other pipe system. 
In small vessels one pump (the donkey) usually serves for 
nearly all purposes, including auxiliary boiler-feed, anc 
on Western river steamers an independent pump (the 
doctor) having a steam-cylinder and walking-beam, drive* 
a system of pumps for feed, fire and bilge-pumping 
service. 


240 






AUXILIARY MACHINERY AND FITTINGS 241 

Ques. 594.—What special features should appertain 
:o the boiler feed-pump? 

Ans.—It should be simple, durable, of great strength 
ind ample capacity to insure regular and reliable service 
mder the most severe conditions. It is always best to 
lave the main and auxiliary feed-pumps duplicates of 
i :ac h other if possible, for the reason that in cases of 

emergency the different 
parts are interchangeable. 
In the marine service the 
main feed-pump draws its 
supply of water from the 
hot well, feed-heater or the 
feed-tank, as the case may 
be. The auxiliary or du¬ 
plicate feed-pump may be 
arranged so as to draw 
from either of these sources, 
and also from the sea, thus 
making provision for 
emergency. 

Ques. 595.—W here 

:c. 158. The Worthington Boieer- 

£ EED oFn u P IP ' a ™ iralty Pattern, should the feed-pumps be 

rOR 6jU BOUNDS PRESSURE. 

located? 

Ans.—As near to the boiler-room as possible, in order 
hat the engineer in charge of the boilers may have full 
ontrol of the feed-water supply. On board of vessels, 
dien the feed-pump is worked from the main engine, the 
uxiliary, or injector is usually placed in the stoke-hold. 
Ques. 596 . —What type of boiler feed-pump has 












242 QUESTIONS AND ANSWERS 

been found to be the most reliable for all kinds of 
service? 

Ans.—The double acting steam-pump, working inde¬ 
pendently of all other machinery. The horizontal variety 
is principally used for land service, while on board steam 
vessels the vertical type is preferred, for the reason that 
it occupies less floor space. In both the horizontal and 
vertical types, the water valve-chambers have removable 
covers, allowing a ready access to the valves and valve- 
seats. The steam-valves of these pumps are actuated in 
various ways. In the duplex variety, which consists of 
two pumps combined into one, the steam-valve of one 
side is moved from the piston-rod of the other, and vice 
versa, while with a pump having but a single steam-cylin¬ 
der, the steam-valve is worked by a tappet action from 
<ts own piston-rod. 

Ques. 597.—What two varieties of feed-pumps are 
largely in use on ocean steamers? 

Ans.—The Weir vertical double-acting steam-pump 
and the Belleville, which is built either vertical or horizon¬ 
tal. In the Weir pump the water-valves are a series of 
small cones milled out of solid metal and give a large 
area of opening with a slight lift. The steam-valve 
arrangement of the Weir pump is rather complicated and 
requires to be maintained in perfect condition, to insure 
good service. It consists of a main valve for distributing 
steam to the cylinder and an auxiliary valve for distribu- 
ting steam to work the main valve. The main valve moves 
horizontally from side to side, being driven bv 
admitted and exhausted from each end alternately. The 


AUXILIARY MACHINERY AND FITTINGS 


24? 


auxiliary valve is actuated by a lever with a fixed fulcrum 
worked by the piston- 
rod of the pump. This 
auxiliary valve moves on 
a flat face on the back of 
the main valve and in a 
direction at right angles 
to the latter. Both the 
main and auxiliary valves 
are simply slide valves, 
but the main valve is half 
round, the round side 
working on the corre¬ 
spondingly shaped cylin¬ 
der port-seat, while the 
back of the valve is flat 
and forms the seat for 
the auxiliary valve. Both 
ends of the main valve 
are lengthened, so as to 
project beyond the port 
face and are turned cylin¬ 
drical, with flat ends. 

Caps are fitted on each 
of these ends, forming 
cylinders which are 
closed at the mouths by 
the flat ends of the main 
valve, which act as pis- 

. , . c . , Fig. 159. Weir's Feed-pump ros 

tons, the length of stroke Marine Service. 
























































































244 


QUESTIONS AND ANSWERS 


that the piston can make being the full travel of the 
valve. The auxiliary valve-seat has three ports, the L 
center one being the exhaust and the two side ports being 
steam-passages leading through the piston ends of the a 
main valve. The right-hand cylinder port-passage is led ^ 
through the left-hand end of the piston and the left-hand , 
passage leads to the other end. These ports admit steam r 
to the two small caps or cylinders at each end of the valve j, 
alternately, by which it is thrown from side to side. : 
Besides the ports already referred to, there are two 
other ports formed on the auxiliary valve-seat leading to 
and corresponding to two ports on the half-round seat of 
the main valve. These ports are for the purpose of 
admitting steam to the top and bottom of the main cylin¬ 
der, and are arranged on the auxiliary valve-seat to cut 
off steam before the end of the stroke, and so reduce the 
speed of the piston, but the expansion chambers at each 
end of the main valve are fitted with by-passes to admit £ 
steam for the full stroke when so desired. This may be 4 j. 
necessary when starting the pump, as then the water- 
cylinder may be full of water. These by-passes are formed < 
by notches cut in the edges of the caps and may be ope led n 
or closed by turning the caps by means of spindles pro- ■ 
vided at each side of the valve-chest, and thus give a* 


definite cut-off. There are separate by-passes for the up „• 

* 

and down strokes, and the silent working of the pump 


depends upon the proper adjustment of these by-passes. 

Ques. 598.—Describe the action of the Belleville feed¬ 
pump. 

Ans.—The pump is double-acting, having an ordinary 





AUXILIARY MACHINERY AND FITTINGS 


245 


flat slide-valve without lap, worked by a curved lever, 
which is moved at each end of the stroke, by a projection or 
lug on the piston-rod. The steam-ports are arranged at 
each end of the cylinder in such a manner as to admit the 
steam uniformly all around the cylinder circumference, 

Id 

and not at the top only, which prevents bending forces 

pi 

on the rod. The steam-pressure remains constant, 

I therefore, until near the end of the stroke, when the pro¬ 
jection strikes the valve-lever and commences to close the 

t 



q steam-valve, so that the steam-pressure falls .and the 
motion would cease, but for special provisions. Before 
the piston can commence the return stroke, it is necessary 
e *that the valve should not only be closed but pushed suffi¬ 
ciently far over to reopen for steam on the other side. 
To enable the steam already in the cylinder to complete 
the stroke and throw the valve over to the opposite side, 
9 an orifice is provided at each end of the water-cylinder, 
closed by levers and communicating with the suction- 
i chamber, so that when the water-piston nears the end of 

















































246 


QUESTIONS AND ANSWERS 


its stroke, it strikes one of these levers and opens the orifice 

I 

to the suction-chamber, thus causing the pressure in the 
water-cylinder to fall, and the steam, although cut off, 
is enabled by its expansive force to push the piston to the 
end of the stroke and reverse the valve. When motion 
begins in the opposite direction the water-valves are a 
series of small valves, generally eight in number, at each 
end, four for suction and four for discharge. Small holes 
about tV inch in diameter, are made through the levers into 



Fig. 161. Kirkaedy’s Feed-heater. 


the passage leading to the suction chamber, so that a 
small quantity of water is always escaping from the water- 
cylinder, which causes the pump to keep slowly in motion, 
even when the feed-valves on the boilers are closed. 

Ques. 599.—Are feed-water heaters much in use in 
the marine service? 

Ans.—They are largely used in the mercantile service/ 
and results justify their adoption. 

Ques. 600.—Describe the construction and operation 
of Kirkaldy’s feed-heater.' 













































AUXILIARY MACHINERY AND FITTINGS 


247 


Ans.—It is constructed along lines similiar to a sur¬ 
face condenser, having tubes rolled into tube-plates in the 
ordinary manner, the whole surrounded by an outside shell, 
leaving spaces at each end between the tube-plates and 
end-covers. The feed-water does not mix with the 

I i 

heating steam, but is drawn through the tubes, on the^ 





—CL. 









mm mm 


DIRECT ST tut 
FROM eonaf." 



Fig. 162. Weir’s Feed-heater and Regulator. 


outside of which is the steam, which is usually the exhaust 
from various auxiliary engines, or it may be drawn from 
the boilers. By-pass valves are fitted, so that when 
necessary the feed-water can be passed direct, without 
passing through the heater. 
























































































248 


QUESTIONS AND ANSWERS 


Ques. 601.—Describe the construction and operation 
of Weir's feed-heater and regulator. 

Ans.—It takes steam from the final receiver of the 
engine after it has done most of its work. The steam 
enters the heating chamber through a circular perforated 
ring and there mixes with the cold feed-water, which is 
admitted through the spring-loaded valve on the cover. 



Fig. 163. The Harris Grease Fieter. 


The heated water falls to the bottom of the heater, from 
whence it is removed by the feed-pump. A galvanized 
iron float is fitted to the bottom of the heater, which 
communicates by means of levers with the steam-valve 
leading to the feed-pump, thus keeping the water-level 
constant in the heater and preventing the pumps from 
drawing air. 




















































































































AUXILIARY MACHINERY AND FITTINGS 249 

Ques. 602.—What provision is made on board steam- 
vessels for the prevention of oil or grease passing into 
the boilers along with the feed-water? 

Ans.—Numerous types of grease-filters are in use. 
In the Harris grease-filter the feed-water is caused to pass 
through a series of gratings, on each of which is fitted 
one or two sheets of filtering material, consisting of 
toweling or flannel, supported by wire gauze. When the 
cloths become dirty they are cleaned by a steam jet, and 
washed ofd by a reverse current of water. 

Ques. 603.—What is the object of placing a governor 
on an engine? 

Ans.—To maintain regularity of speed of the engine 
when the load is varied from any cause. 

Ques. 604.—Upon what principle do the most of the 
1 governors for land engines operate? 

Ans.—Upon the principle of centrifugal force causing 
two balls or weights, each suspended or attached to a lever 
swinging on a fulcrum, fixed near the top of a vertical 
revolving spindle, to fly outward as the speed increases; 
and the force of gravitation which acts in the opposite 
direction as the speed decreases. The outward movement 
of the balls or weights is utilized to either close the throt¬ 
tle or shorten the point of cut-ofif, while the inward move- 
nent has the opposite efifect. 

Ques. 605.—Are governors required on marine en¬ 
gines? 

Ans.—They are, for the reason that in a marine engine 
considerable diminution in resistance may ensue in rough 
or stormy weather, from the pitching motion of the vessel, 




250 


QUESTIONS AND ANSWERS 


which causes the propellers to rise partly out of the water 
thus causing what is technically known as ''racing o 
the engines. ,, 

Ques. 606.—Is the centrifugal type of governor suit 
able for marine service? 

Ans.—It is not, for the reason that the forces acting 
upon the balls or weights would be affected by the motiot 
of the ship and the action would be irregular. Othei 
forms of governors for marine engines are in use witl 
various degrees of success, but all, or nearly all of them 
possess the one defect of requiring an increased speed oi 
the engine to cause them to act, and even then their actior 
is sluggish, the throttle-valve being generally closed after 
the racing is over. 

Ques. 607.—What type of marine governor is 1 ikely 
to prove the most successful in marine service for the 
prevention of “racing?” 

Ans.—A governor that acts by variations of pressure 
at the stern of the vessel near the propeller, and not 
from engine-speed variations. Racing being caused by 
diminished immersion of the propeller, it is accompanied 
by a diminution of pressure of water at that part, which 
can be utilized to actuate the throttle-valve. Such gov¬ 
ernors may therefore anticipate and prevent any increase-' 
of speed due to the above cause, although they would have 
no effect in case of a serious increase of speed, due to 
such an accident as a broken shaft or propeller. 

Ques. 608.—Describe Dunlop’s governor, which is of 
the latter type. 

Ans.—It consists of a sea-cock at the stern of the 








AUXILIARY MACHINERY AND FITTINGS 


251 


ship, opening into an air-vessel or air-chamber, so com 
: structed that, by opening the sea-cock, water flows into 
the air-vessel and compresses the air contained therein to 
a pressure equivalent to the head of water outside the 
ship. From the top of the air-chamber a pipe is led to 
the under side of an air-tight elastic diaphragm, forming 
i part of an apparatus in the engine-room. On the upper 
side of the diaphragm is a spiral spring, with means of 
adjusting its compression to balance the air pressure 
below the diaphragm. From the center of the diaphragm 
a connection is made to the slide-valve of a small steam- 
cylinder so constructed that its piston moves in exact 
accordance with the movements of the diaphragm. This 
steam-piston is connected by suitable gear to the throttle- 
valve of the engine whose speed is to be controlled. The 
action is as follows: The sea-cock being open, any varia¬ 
tion of head of water outside the ship is accompanied by 
an inflow or outflow of water through it and consequently 
a variation in the pressure of the air contained in the air- 
chamber, and also under the diaphragm of the engine-room 
apparatus, causing the diaphragm to move through such 
part of its travel as is requisite to enable the compression 
of spring and the air-pressure to balance each other again. 
Every movement of the diaphragm is followed by a 
corresponding movement of the governor steam-piston, 
and consequently of the throttle-valve of the engines 
under control, the time taken between the variation in 
the head of water at the stern of the ship and the moving 
of the throttle-valve being practically nothing. The 
governor therefore anticipates any increase in the speed 







252 


QUESTIONS AND ANSWERS 


of the engines due to the propeller rising out of the water 
and does not depend upon a variation in speed of the 
engines to be controlled, before it acts. By adjusting the 
balance between the spring and the air-pressure under the 


diaphragm the diaphragm begins to fall and the throttle-, 
valve to close, when the tips of the propeller-blades rise 



to any desired distance above the surface of the water. 
The air-vessel should be fitted as far aft in the screw-tun¬ 
nel as possible, the hole through the side of the vessel 
being placed about one-fourth the diameter of the 
propeller below the level of the center of the shaft. The 
reports of the action of this governor in the mercantile 



















































































AUXILIARY MACHINERY AND FITTINGS 


253 


marine are very satisfactory. It is fitted in the “Cam¬ 
pania/’ “Paris,” and many other vessels. 

Ques. 609.—How is the fresh water needed on board 
ship for drinking, washing, culinary purposes, and for 
making up for the waste of feed-water for the boilers and 
for various other purposes, obtained? 



Normandy’s Evaporator. 




1 

a 

f 

l 

i 

I 


Ans.—By means of evaporators and distillers. The 
evaporators are really small boilers, with heat obtained 
from steam passing through tubes, while the water to be 
evaporated surrounds the tubes. There is no coal used 
in these boilers, the steam being obtained from the main 





































































































































































































£54 


QUESTIONS AND ANSWERS 


boilerSc The vapor produced is conducted to the distillinj 
apparatus, where it is condensed into fresh drinkinj 
water, and a portion of it goes to the condensers for th 
purpose of making up the deficiency of boiler feed-water 
The condensed primary steam is returned to the boilers. 

Ques. 610.—Describe Normandy’s evaporator. 

Aps. —In this type of evaporator the tubes are a! 
straight and rolled into tube-plates at their ends. Th 
steam from the main boilers enters these tubes through 
pipe at the top and evaporates the surrounding sea-wate 
contained in the shell, and is itself condensed and passe 
out through the bottom, returning to the boilers. Th 
vapor generated outside the tubes is conveyed by a valv 
and pipe, either to the auxiliary condenser for feed-wate 
make-up, or else to the distilling condensers for th 
production of drinking water. The resulting scale i 
deposited in the evaporator, from whence it is cleaned a 
intervals. The sea-water for the evaporator is supplie 
by a pump. It takes its supply from a feed-box contain 
ing a float which maintains a constant level in the feed 
box. 

Ques. 611.—Describe Normandy’s condenser. 

Ans.—The steam from the evaporator enters the con 
denser through a pipe at the top and passes downwaru 
through two series of tubes, the upper set being th 
condensing and the lower the cooling tubes. These tube 
are surrounded by a casing, which is kept filled with col 
feea-water that enters at the bottom and flows out at th 
top through an overflow pipe that is connected to th 
casing at a point a short distance below the top and i 



AUXILIARY MACHINERY AND FITTINGS 


255 


ghen carried to some distance above the top of the cham¬ 
ber before discharging overboard. By means of this 
Arrangement the hottest sea-water is not discharged over- 
r.oard, but instead may be used in the evaporator, in 
onnection with the condenser, and thus promote economy 
f evaporation. An air-pipe is fitted to allow the air 
Evolved from the condensing water in the casing by heat 
b pass into the overflow pipe leading to the sea. The 

J Dndensed water rises from the lower chamber through a 
:and-pipe connected at the bottom and overflows from 
esiis pipe into and down another pipe leading to the suction 
b a small steam donkey pump, which pumps it into test- 
v^inks, from whence it flows by gravity to the water-tanks 
^ the hold of the vessel. By this arrangement the cool- 
■ tg tubes of the condenser are always kept full of water 
ind the fresh water is drawn off cold. 

2 Ques. 612.—On vessels carrying cargoes of fresh 
o eat and other perishable articles that are affected by 
Due heat, what provision is made for their preservation? 
d Ans.—Various types of refrigerating machinery are in 
;e, some using the cold-air system, others the carbonic- 
:id system, and a few of the smaller ships are fitted with 
n achines for making ice only, 
i Ques. 613.—Describe the cold-air system, 
fo' Ans.—The machine consists of a tandem compound 
eigine having piston slide-valves both on the same valve- 
I<»d and worked by a single eccentric. This engine 
Applies the motive power of the apparatus. Two air- 
i finders, one called the compressing cylinder and the other 
i ie the expanding cylinder, are placed side by side and in 







256 


QUESTIONS AND ANSWERS 


line with the low-pressure cylinder of the engine. Thes 
air-cylinders are double acting, the pistons receiving thei 
motion from the crank-shaft driven by the engine. Th 
action of the device is simple and is as follows: Th 
revolving shaft, through the medium of connecting rod 
and guides, moves the pistons up and down. Air i 
drawn into the compressing cylinder through inlet-valve 
from the surrounding atmosphere or from the cold room 
It is compressed on the return stroke of the piston am 
passes into the cooling chamber, which is constructe 
similar to a surface condenser, having a pump to circu 
late the cooling sea-water through it. The work done thu 
far appears as heat in the air and this heated air, passinj 
through the tubes of the air-cooler, is cooled by the cir 
dilating water and is then led to the valve-chamber of th 
expanding cylinder. The valve arrangement of thi 
cylinder consists of a slide-valve and an expansion valv 
working on the back of the slide-valve. This arrange 
ment supplies a means of sharply cutting off the inlet o 
air when it enters the expanding cylinder. The compress 
ing cylinder is provided with a water-jacket throug 
which the circulating pump delivers the cooling water o 
its way from the air-cooler to the sea. The slide-valve 
are so arranged in the expanding cylinder that when th 
proper quantity of air is admitted the supply is cut ol 
and during the remainder of the stroke the air expand 
and therefore does work on the piston and heat i 
expended in the process in exactly the converse manne 
to the generation of heat in the compressing cylindei 
As, however, the air has been deprived of its surolus hea 






AUXILIARY MACHINERY AND FITTINGS 



Fig. 165. Cold-Air System of Refrigeration 






















































































































































































































































































































£58 QUESTIONS AND ANSWERS 

in the cooling chamber, the heat eg m valent of the work i 
does in the expanding cylinder is absorbed from itself an 
the result is a considerable lowering of its temperature 
This cold air is then exhausted through the orifice of th 
slide-valve in the usual manner, and conducted first to th 



Fig. 166. Carbonic-Acid System oe Refrigeration. 


*snow-box” a small accessible chamber in which the sno 
formed from the moisture is deposited, and from thence 1 
the cold chamber, in which the supply of meat or prov 
sions is kept and where it displaces air of a higher ten 
perature. The refrigerating chamber is insulated t 
lagging its bulkheads, ceiling, and floor with silicate cotu 






































































































AUXILIARY MACHINERY AND FITTINGS 259 ' 

Dr other non-conductor, a teak lining being fitted c> er 
this to form the inside surface. 

Ques. 614.—Describe the carbonic-acid system. 

Ans.—A very successful and efficient device is the 
carbonic-anhydride system of Messrs. J. & E. Hall, in 
which carbonic anhydride is passed round continually in 
;he circuit. The apparatus consists of three parts: a 
:ompressor, a condenser, and an evaporator. The com¬ 
pressor draws in heated and expanded gas from the 
;vaporator and compresses it. The compressed gas then 
passes to a condenser, consisting of coils in which the 
varm compressed gas is cooled and liquefied by reduction 
pf temperature caused by the action of the cooling sea- 
vater. From the condenser the cool liquid carbonic 
mhydride is conveyed into the evaporator consisting of 
:oils, where it vaporizes and expands, absorbing heat in 
he process and cooling the surrounding brine, which is 
( n contact with the coils. This cold brine is circulated 
>y a small pump to the refrigerating chamber, where it 
s conducted through a long series of rows of cooling 
>ipes, termed “grids,” which are placed at the roof of 
he chamber. The cold-brine “grids” in this position set 
ip a circulation of air, the cold air descending and being 
eplaced by air not so cold, which is cooled in its turn. 
Vny moisture in the air is condensed on the “grids” and 
ippears as frost on the pipes. The theory of the action 
)f this system is as follows: Under atmospheric pressure 
he liquid C0 2 would evaporate at a temperature of 

L20 degrees Fahrenheit below zero, but its temperature of 

< 

“vaporation rises with the pressure, in a similar manner as 








260 


QUESTIONS AND ANSWERS 


water. At a pressure of 500 pounds per square inch i 
boils at a temperature of 30 degrees Fahrenheit so tha 
cold water may be used to supply the heat for boiling i1 
The pressure in the evaporator is therefore regulated t 
the required temperature of the cooling water, so that 
considerable pressure is necessary in the evaporator. Th 
compressor draws the gas from the evaporator and com 
presses it to the liquefying pressure, the heat due to th 
compression being absorbed by the cooling water in th 
condenser coils and the gas in these coils becomes liqui 
before its exit. The liquid is then boiled in the evapora 
tor coils, cooling the surrounding brine by the hea 
absorbed during evaporation. The compressor gland i 
made tight by cupped leathers with glycerine force 
between them at a higher pressure than that in the com 
pressor, so that no escape of gas can take place. Th 
carbonic anhydride is supplied in steel cylinders t 
replenish the supply. 

Ques. 615.—What types of dynamos are used on boar 
ships for generating electric current for internal ilium 
nation and for working search-lights and motors? 

Ans.—They are usually of the two-pole type, dire( 
driven and carried on an extension of the engine-be* 
They have drum armatures and the field-magnets ai 
compound wound, to give a constant pressure of 80 c 
100 volts for any current from zero to the maximun 
while the speed is maintained constant. The usual spe( 
is 320 revolutions per minute. The machines are cor 
nected to a switchboard located in a central position, fro: 
which the current is distributed to the various circuits fc 





AUXILIARY MACHINERY AND FITTINGS 


261 


^hting, motors, etc. This board is so arranged that a 
rcuit can be quickly changed from one machine to 
lother, but no circuit can receive current from two 











































































































































262 


QUESTIONS AND ANSWERS 


machines at the same time. The most recently fitte 
dynamos for the marine service are of the iron-clad typ< 
the field coils and the armature being almost entirel 
surrounded by iron, to reduce to a minimum the leak 
age of magnetic lines of force which may affect coir 
passes or chronometers in the neighborhood. 

Ques. 616.—How are these dynamos usually driven? 

Ans.—By vertical two-cylinder engines, generall 
compounded, although in some ships, where the steair 
pressure is low, the engines are simple. All parts ai 
carefully balanced and a heavy fly-wheel is fitted on th 
engine-shaft, at the dynamo end, which conduces to stead 
running. The speed is regulated by an isochronal governc 
fitted on the shaft. 

Ques. 617.—Describe the construction of the arma 
ture. 

Ans.—The armature-core is built up of thin disks c 
soft iron slipped over metal sleeves, which are keyed o 
the shaft. The disks are insulated from each other b 
thin sheets of asbestos paper, to prevent loss of energ 
and heating due to eddy currents, and are kept in plac 
by clamping-plates and end-nuts. The conductors on tf 
armature, which carry the current, are made up of copp' 
wires, twisted together, and pressed to a rectanguk 
section. They are insulated by a covering of varnishe 
tape. Usually two lengths of bars are used. They ai 
placed around the periphery of the armature, longitud: 
nally, long and short bars alternating, their ends overhang 
ing the core. All the ends at one end of the armatui 
project the :ame distance. Projections are fitted into tl 


AUXILIARY MACHINERY AND FITTINGS 


263 



core at intervals, which drive the conductor-bars. These 
projections are insulated by mica slips. The bars are 
kept in place by bands of steel or bronze binding wire, 
tightly wound on and soldered. Mica strips are placed 
under the bands to prevent injury to the insulation of the 
bars. Each bar is connected at each end by bent copper 
strips to another bar almost diametrically opposite to it, 
so that the whole of the bars and end-connections form 
one closed circuit. The projecting end of each long bar 
is also connected to the nearest commutator segment, the 
number of segments being equal to the number of long 


Fig. 168. Armature 

bars. Two or more pairs of brushes bear on the commu¬ 
tator, to collect the current, so that any brush may be 
lifted off without interrupting the circuit. 

Ques. 618.—Describe the construction of the field- 
magnet coils. 

Ans.—The field-magnet winding consists of shunt and 
series coils wound on a frame which fits over the 
upper pole-piece. The shunt coils are of small 
wire and high resistance. The ends of the wire 
are connected to the machine terminals. The greater 
part of the magnetism is due to these coils, so that at full 
speed, and when no current is being taken from the 








264 


QUESTIONS AND ANSWERS 


machine, the electric pressure is normal, that-is, 80 of 
100 volts. The series coils are formed of thick copper 
bars and convey the whole current generated. The> 
provide additional magnetism, proportional to the current 
flowing in them, and so compensate for the additional 



pressure required to force this current through th< 
machine. By the combination of the two sets of coils, th< 
pressure is thus independent of the current, so long as th< 
speed is constant. In the largest machines there are tw< 
distinct armature windings laid on side by side, the bar 















































































AUXILIARY MACHINERY AND FITTINGS 265 

)f the two windings alternating, as also do their respec- 
ive commutator segments. The two windings are con* 
lected in parallel by the brushes, which all have a bearing 
•ather wider than the angular width of two commutator 
Segments. 

Ques. 619.—In order to obtain satisfactory working, 
vhat should be done with the commutator occasionally? 

Ans.—It should be turned up, by using a lathe slide- 
est clamped to the bed-plate and running the engines as 
lowly as possible, and after turning, the commutator 
jhould be polished. This truing up is necessary in order 
o remove any flat places which are liable to form on the 
egments. The brushes also should be carefully filed to 
it the commutator curve. The brushes must be care- 
ully set in the holders, with all the tips of each set in a 
ine, and the tips of the two sets bearing simultaneously 
m diametrically opposite commutator segments. Gener- 
lly two segments are marked at their ends, with crosses, 
o assist in this adjustment. 

Ques. 620.—How is the electric current carried to the 
.ifferent parts of the ship? 

Ans.—By wires of the best copper, thoroughly insu- 
ated and protected from injury by being placed in wooden 
nouldings, or what is still better, iron tubes lined with 
nsulating material. The junction boxes have safety 
uses and connections, arranged in incombustible porce- 
ain or lava blocks. 

Ques. 621.—How are the lamps and motors arranged? 

Ans.—The lamps are attached to substantial supports 
yith good protection to the insulation of the wires at their 







266 


QUESTIONS AND ANSWERS 


connection. For exposed places extra globes or wire 
screens are provided to prevent breaking of the bulbs. 
The motors are fitted on substantial foundations, with: 
switches for handling in convenient positions. The use : 
of electric motors is becoming more and more general on 
board vessels as their convenience and freedom from 
waste is known. They can be used for working ven¬ 
tilating fans, etc., in confined spaces where the heat of 
steam would be objectionable. They also avoid the waste 
due to condensation, radiation and leakage in pipes, 
require very little attention when running and are always 
ready for starting. 

Ques. 622.—What facilities are provided for pumping 
the water out of steam-ships in case of a serious leak? 

Ans.—All steam-ships, including war-vessels, were 
formerly fitted with bilge-pumps worked direct from the 
main engines, and this is still the common practice in the 
mercantile marine. In addition to these pumps, the 
circulating pumps are fitted with bilge as well as sea 
connections, and in some of the larger vessels there are 
four centrifugal pumps which can be used for pumping 
out the bilges, each of these pumps having a capacity of 
at least 1,200 tons of water per hour. 

Ques. 623.—What are some of the requirements of a 
reliable bilge-pumping outfit? 

Ans.—The pump itself should be close to the bilge, 
but the engine for working it should if possible be at a 
high level, so as to be out of the reach of the water in 
case of its rising rapidly. Another point that should be 
kept in view is the provision of large engine-power for 




AUXILIARY MACHINERY AND FITTINGS 267 

vorking the pumps. The valves for changing the suction 
)f the centrifugal pumps from the sea to the bilge are, or 
it least should be, arranged to be worked from the start- 
ng platform, and to enable this to be done quickly in 
ase of need, the valves in the sea and bilge-suction pipes 



tavy. 


















































































































































































•268 


QUESTIONS AND ANSWERS 


Ans.—Each pumping engine consists of two double¬ 
acting pumps and two steam-cylinders, fitted with 
slide-valves, having very little lap, to insure the engines 
starting readily from any position of the cranks, economy 
m the use of steam being in these cases a minor considera¬ 
tion. In the large battle-ships and cruisers there are four 
,of these pumps, two in each engine-room, each one of the 
four having a capacity of 80 to 120 tons of water per 
hour. The pumps are large enough to remove these 
quantities of water at a speed not exceeding 60 revolu¬ 
tions per minute, with a steam-pressure of two-thirds 
the maximum boiler-pressure, and they form a means of 
pumping water out of the ship, auxiliary to the main 
circulating pumps. They can be used for either fire ser¬ 
vice or for clearing the bilges of water. 

Ques. 625.—Describe Friedmann’s bilge-ejector. 

Ans.—This apparatus is a modification of Giffard’s 
injector, the number of nozzles being increased so as to 
give the steam several suction orifices instead of one. 
The steam is conducted to a tuyere about one-half the 
diameter of the steam-pipe, and then passes successively 
through a series of intermediate tuyeres, through which 
the water is drawn from the hold and expelled from the 
ship through the discharge. The device occupies little 
space and has considerable capacity, but its consumption 
of steam is large. 

Ques. 626.—Describe the suction and discharge 
arrangements of fire and bilge pumps. 

Ans. They are fitted with separate suction-pipes 
leading to the following parts of the vessel: Forward 


AUXILIARY MACHINERY AND FITTINGS 


269 


and after ends of engine-room, with a continuation to 
the screw tunnel from the latter, main engine save-all, 

V 

each boiler compartment, the main suction-pipe, salvage 
system of the vessel and to the sea. The valve-boxes 
and pipes are so arranged that each pump can draw from 
any of these parts. The pumps deliver water either over' 
board direct, to the engine-room or to the fire-main, a 
large air-vessel being fitted in connection with the latter. 



DISCHARGE r DISCHARGE 

TO EIRE MAW y l OVERBOARD- 

\ I 


DISCHARGE TO 
ENGINE ROOM**' r=»1 



s cross Connection 
B crnec#' suction boxes 


TO ATTER ENGINE ROOM D 
* SCREW TUNNEL - — 


SUCTION FROM 
SALVAGE SYSTEM. 



Fig. 171. Suction and Discharge Arrangements of Fire and Bilge Pumps. 

A A A A, pumps; B B, directing valve-boxes; C C. shut-off valves from 
the sea, and bilge directing valve-box respectively; D D, directing valves for 
discharge, either to fire main, overboard or to engine-room. 

. 

Ques. 627.—How is the fire-main arranged? 

Ans.—The fire-main is a pipe extending fore and aft 
in the ship, with branches leading to different parts as 
required. Delivery-valves, with screwed nozzles for hose- 
connections, are located at various points in the fire-main. 
Non-return valves are fitted at the junction of delivery- 
pipes from the pumping engines. 









































































CHAPTER IX 


THE INDICATOR— PRINCIPLES OF THE INDICATOR 

Ques. 628.—By whom was the indicator invented anc' 
first applied to the steam-engine? 



Fig. 172. Sectional View Crosby Indicator. 


Ans.—The indicator was invented and first applied t 

the steam-engine by James Watt, whose restless geniu 

270 









































































































THE INDICATOR-PRINCIPLES OF INDICATOR 27 1 

ras not satisfied with a mere outside view of his engine 
s it was running, but he desired to know more about the 
ction of the steam in the cylinder, its pressure at differ- 
nt portions of the stroke, the laws governing its expan¬ 
ion after being cut off, etc. Watt’s indicator, although 
rude in its design and construction, contained embodied 
within it all of the principles of the modern instrument. 

Ques. 629.—What are the principles governing the 
ction of the indicator? 

Ans.—First, the pressure of the 
team in the engine-cylinder throughout 
n entire revolution, against a small pis- 
on in the cylinder of the indicator, which 
a turn is controlled or resisted in its 
novement by a spring of known tension, 
o as to confine the stroke of the indica- 
or piston within a certain small limit, 
iecond, the stroke of the indicator pis- 

1 n is communicated by a multiplying 
echanism of levers and parallel motion 
a pencil moving in a vertical straight 
le, the distance through which the pencil moves being 
>verned by the pressure in the engine-cylinder and the 
nsion of the spring. Third, by the intervention of a re- 
icing mechanism and a strong cord, the motion of the pis- 
_n of the engine throughout an entire revolution is com- 
aunicated to a small drum attached to and forming a part 
if the indicator. The movement of the drum is rotative 
.nd in a direction at right angles to the movement of the 
)encil. The forward stroke of the engine-piston causes 



Fig. 173. 

Crosby Indicator 
Spring. 

















272 


QUESTIONS AND ANSWERS 


the drum to rotate through part of a revolution and al 
the same time a clock-spring connected within the drurr 
as wound up. On the return stroke the motion of the 
drum is reversed, and the tension of the spring returns 1 
the drum to its original position and also keeps the core 
taut. 

Ques. 630.—Describe in general terms the construe 




1 ij 

m) 

isl 


m 



- =-. 



/ | j* 1 J 


Fig. 174. 


tion of an indicator. 

Ans.—An indicator con¬ 
sists of a small cylinder, 
open to the atmosphere al 
the top and having its bot 
tom end connected by suit 
able pipes and stop-cocks 
to both ends of the engine 
cylinder in such a mannei 
that the steam-pressure in 
either end may be caused 
to act upon the indicator 
piston, as required. The 


Sectional View Thompson Indicator. .. , - A . ... 

cylinder of the indicator 

stands vertical, and is of a known area, usually about one 
square inch. It contains a piston, upon which the steam 
acts only on the under side, the top of the cylinder being 
open to the atmosphere. The length of stroke of this 
piston is regulated and controlled by a steel spiral spring 
of known tension, which acts in resistance to the pressure 
of the steam. When the cock connecting the cylinders of 
the engine and indicator is closed, both ends of the indi¬ 
cator cylinder are open to atmospheric pressure, and the 





























































































THE INDICATOR-PRINCIPLES OF INDICATOR 273 

encil, which is connected to the piston by a system ol 

vers, stands at its neutral position. 

Ques. 631.—Describe the construction and action iV 

le spiral spring inxonnection with the indicator piston. 

Ans.—These springs are made of different tensioi.s in 

rder to be suitable to different steam-pressure? and 

Deeds, and are numbered 20, 40, 60, etc., the ni ,mber 

leaning that a pressure per square inch 

i the engine-cylinder corresponding to 

le number on the spring will cause a 

ertical movement of the pencil through 

distance of one inch. Thus, if a No. 

.) spring is used and the pressure in the 

blinder at the commencement of the 

: roke is 20 pounds per square inch, the 

mcil will be raised one inch, or if the 

pressure is 30 pounds, the pencil will 

avel V /2 inch, and if there is a vacuum 

: 20 inches in the condenser, the pencil 

ill drop ^2 inch below the atmospheric 

le for the reason that 20 inches of vac- Thompson indica¬ 
tor Spring. 

jm correspond to a pressure of about 
) pounds less than atmospheric pressure or an absolute 

1 

-essure of about 4 pounds. If a 60 spring is used a 
-essure of 60 pounds in the engine-cylinder will be re¬ 
tired to raise the pencil one inch, or 90 pounds to raise 
V /2 inch. 

Ques. 632.—Are these springs placed inside the 
dinder in all types of indicators? 

Ans.—The Ashcroft Manufacturing Company of New 


















274 QUESTIONS AND ANSWERS 

York, makers of the well-known Tabor indicator, have 
recently introduced a new feature in indicator work by 
connecting the spring on top of the cylinder and in plain 



FlG. 176. Improved Tabor Indicator with Outside Connected Spring. 

Ashcroet Meg. Co., N. Y. 


view of the operator. This arrangement removes the 
spring from the influence of direct contact with the 
steam, and it is subject only to the temperature of th< 














































































































THE INDICATOR—PRINCIPLES OF INDICATOR 275 

I 

Irrounding atmosphere. It is claimed that as a result 

I this the accuracy of the spring is insured and that no 
owance need to be made in its manufacture for 
jpansion caused by the high temperature to which it is 

I bject when located within the cylinder. Another good 
iture of this design is, that the spring can be easily 

I noved without disconnecting any one part of the 
drument in case it is desired to change springs. 

Ques. 633.—What precautions should be observed in 
laching the indicator to an engine-cylinder? 

I Ans.—The main requirements in these connections 
5 that the holes shall not be drilled near the bottom of 
5 cylinder where water is likely to find its way into 
; pipes, neither should they be in a location where the 
ush of steam from the ports will strike them directly, 
r where the edge of the piston is liable to partly cover 
;m when at its extreme travel. An engineer before he 
tdertakes to indicate an engine shoull satisfy himself 
lit all these requirements are fulfilled. Otherwise he is 

I t likely to obtain a true diagram. The cock supplied 
th the indicator is threaded for one-half inch pipe, and 
jless the engine has a very long stroke it is the practice 
i bring the two end connections together at the side or 
b of the cylinder and at or near the middle of its length, 
( ere they can be connected to a three-way cock. The 

1 >e connections should be as short and as free from 
ows as possible, in order that the steam may strike 
; indicator piston as nearly as possible at the same 
aiinient that it acts upon the engine-piston. These pipes 
buld always be thoroughly blown out and cleaned, by 





276 


QUESTIONS AND ANSWERS 


allowing the steam to blow through the open three-wa 
cock during several revolutions of the engine before cor 
necting the indicator. If this is not done there is a mor< 
certainty that dirt and grit will get into the cylinder c 
the indicator and cause it to work badly and gi\ 
diagrams that are misleading. 

Ques. 634.—How is an indicator diagram or cai 

drawn? 



Fig. 177. Three-way Cock. 


Ans.—To the outside of the drum a piece of blar 
paper of suitable size is attached and held in place by tv 
clips. Upon this paper the pencil in its motion up ai 
down traces a complete diagram of the pressures ai 
other interesting events transpiring within the engin 
cylinder during the revolution of the engine. In fact, t 
diagram traced upon the paper is the compound result 
two concurrent movements. First, that of the pen 
caused by the pressure of the steam against the indicat 

























T1IE INDICATOR-PRINCIPLES OF INDICATOR 277 


iston; second, that of the paper drum caused by, and 
oincident with the motion of the engine-piston. 

Ques. 635.—How is the atmospheric line drawn? 

Ans.—By holding the pencil to the paper, and causing 

he drum to be rotated, when the pencil stands at its neutral 

\ 

osition, that is with the steam shut off from the indica- 
)r cylinder. 

Ques. 636.—What is meant by the term atmospheric 
ne? 

Ans.—The atmospheric line is a horizontal line drawn 
n the diagram and means the line of atmospheric pres- 
jre. If the engine is a non-condensing engine the pencil 
i tracing the diagram will, or at least should not fall 
elow the atmospheric line at any point, but will on the 
aturn stroke trace a line called the line of back pressure 
t a distance more or less above the atmospheric line and 
ery nearly parallel with it. If the engine is a condensing 
agine the pencil will drop below the atmospheric line 
diile tracing the line of back pressure on the diagram, 
nd the distance this line is below the atmospheric line 
dll depend upon the number of inches of vacuum in the 
ondenser. 

Ques. 637.—Is the atmospheric line a necessary part 
f an indicator diagram? 

, Ans.—The atmospheric line is a very important factor 

a the study of the diagram. 

Ques. 638.—How are the dimensions of the diagram 

egulated? 

Ans.—Jt is a convenient practice to select a spring 
lumbered one-half of the boiler-pressure as, for instance, 





278 


QUESTIONS AND ANSWERS 



suppose gauge-pressure or boiler-pressure is 200 pourn 
per square inch, then a 100 spring would give a diagra 
2 inches in height, which is a convenient height. As 
the length of the diagram, this is regulated by adjustmei 


Fig. 178. Crosby Reducing Wheel Attached to Indicator. 

of the cord in its travel, by means of the reducing whe 
Any length of diagram up to four inches may be obtaine 
but two and a half to three inches is a very good leng 
for analysis. 

Ques. 639.—How is the motion of the crosshead 






































THE INDICATOR-PRINCIPLES OF INDICATOR 279 


the engine reduced and utilized for rotating the drum of 
the indicator? 

Ans.—There are various mechanisms used for this 
purpose. Probably the only practically universal 



mechanism lor reducing the motion of the crosshead is 
the reducing wheel, a device in which, by the employment 
of gears and pulleys of different diameters, the motion is 
reduced to within the compass of the drum, and the 


































































280 


QUESTIONS AND ANSWERS 


device is applicable to almost any make of engine, 
whether of high or low speed Some makers of indicators 
attach the reducing wheel directly to the indicator, thus 
producing a neat and very convenient arrangement, 

Ques. 640.—Describe the construction of the wooden 

pendulum for reducing the motion. 

. Ans.—It consists of a flat strip of pine or other light 



wood of a length not less than one and a half times the 
stroke of the engine, and if made longer it will be better. 
It should be from Y\ to /y 8 inch thick and have an average 
width of about 4 inches. If the engine to be indicated is 
horizontal the bar or pendulum is to be pivoted at a fixed 
point directly above and in line with the side of the cross¬ 
head, as that is generally the mo^t convenient point of 
attachment. The pivot can be fixed to a permanent 



























THE INDICATOR—PRINCIPLES OF INDICATOR 281 

standard bolted to the frame of the engine or it may be 
secured to the ceiling of the room or even to a post 
fastened to the floor. If the engine is vertical the bar 
can be pivoted to the wall of the room or a strong post 
firmly secured to the floor. The connection with the 
crosshead is best accomplished by means of a short bar or 
link. A convenient length for this bar is one-half the 
stroke of the engine. 

Ques. 641.—When the short bar is one-half the 
length of the stroke, how is the correct point for the loca¬ 
tion of the pivot for the pendulum found? 

Ans.—Place the engine on the center with the cross- 
head at the end of the stroke towards the crank. Then 
having previously bored a hole for the pivot in one end 
of the pendulum bar and in the other end a hole for con¬ 
necting with the link, suspend the pendulum by a 
temporary pin, as a large wood screw, directly above and 
in line with the stud or bolt hole which has previously 
been tapped into the crosshead at any convenient point. 
The pendulum should be temporarily suspended at such 
a height that when it hangs perpendicular the hole in its 
lower end will line up accurately with the hole or stud in 
the crosshead. Now swing the pendulum in either direc¬ 
tion a distance equal to the length of the link (one-half 
the stroke of the engine) from the crosshead connection 
and note the distance that the bottom hole is above a 
straight edge laid horizontal and in line with the center 
of the stud in the crosshead. This will give the total 
vibration of the free end of the link from a line parallel 
with the line of the engine and the permanent location of 







ggg QUESTIONS AND ANSWERS 

the pivot should be one-half of this distance below the 
temporary point of suspension. This will allow the link 
to vibrate equally above and below the center of its con¬ 
nection with the crosshead. 

Ques. 642.—How is the correct point of attachment 

of the cord to the pendulum found? 

Ans.—The cord can be attached to the pendulum at a 
point near the pivot, which will give the desired length of 
diagram. This point can be determined by multiplying 
the length of the pendulum by the desired length of dia¬ 
gram and dividing the product by the stroke. For 
convenience these terms should be expressed in inches. 
Thus, assume stroke of engine to be 48 inches, length of 
pendulum l l A times length of stroke = 72 inches. 
Desired length of diagram 3 inches. Then 72X3-^48 — 4.5 
inches, which is the distance from center of pivot to point 
of connection for the cord. This can be either a small 
hole bored through the pendulum or a wood screw to 
which the cord can be attached. From this point the 
cord should be led over a guide pulley located at such 
height that when the pendulum is vertical the cord will 
leave it at right angles. After leaving the guide pulle> 
the cord can be carried at any angle desired. 

Ques. 643.—How shoulu the indicator be cared for? 

Ans.—The indicator should be cleaned and oilec 
both before and after using. The best material foi 
wiping it is a clean piece of old soft muslin of fine texture 
as there is not so much liability of lint sticking to o 
getting into the small joints. Use good clock oil for tb 
joints and springs, and before taking diagrams it is a goo< 





THE INDICATOR-PRINCIPLES OF INDICATOR 283 

practice to rub a small portion of cylinder oil on the 
piston and the inside of the cylinder, but when about to 
put the instrument away these should be oiled with clock 
oil also. 

Ques. 644.—How may the cord be adjusted to proper 
length? 

Ans.—None but the best cord should be used for con¬ 
necting the paper drum with the reducing motion, as a 
cord that is liable to stretch will cause trouble. After 
the indicator has been screwed on to the cock connecting 
with the pipe, the cord must be adjusted to the proper 
length before hooking it on to the drum. This must be 
done while the engine is running, by taking hold of the 
loop on the cord connected with the reducing motion 
with one hand, and with the other hand grasp the hook 
on the short cord attached to the drum, then by holding 
the two ends near each other during a revolution or two 
it will be seen whether the long cord needs to be shortened 
or lengthened. 

Ques. 645.—What precautions are necessary in regard 
to the paper and pencil in order to secure a truthful 
diagram? 

| Ans.—Care should be exercised in placing the paper 
on the drum to see that it is stretched tight and firmly 

II i 

held by the clips. The pencil point having been first 
sharpened by rubbing it on a piece of fine emery cloth or 
sand paper should be adjusted by means of the pencil 
stop with which all indicators should be provided, so that 
it will have just sufficient bearing against the paper to 
make a fine, plain mark. If the pencil bears too hard on 



284 


QUESTIONS AND ANSWERS 


the paper it will cause unnecessary friction and the dia¬ 
gram will be distorted. The best method of ascertaining 
this fact and also whether the travel of the drum is 
equally divided between the stops, is to place a blank dia¬ 
gram on the drum, connect the cord and while the engine 
makes a revolution hold the pencil against the paper. 

i 

Then unhook the cord, remove the paper and if the travel 
of the drum is not divided correctly it can be changed. 

Ques. 646.—Describe the process of taking an indica¬ 
tor diagram. 

Ans.—Place a fresh blank on the drum, being careful 
to keep the pencil out of contact with it, connect the cord, 
open the cock admitting steam to the indicator and after 
the pencil has made a few strokes to allow the cylinder to 
become warmed up, then gently swing it around to the 
paper drum and hold in there while the engine makes a 
complete revolution. Then move the pencil clear of the 
paper, close the cock and unhook the cord. Now trace 
the atmospheric line by holding the pencil against the 
paper while the drum is revolved by hand. This method 
of tracing the atmospheric line is preferable to that of 
tracing it immediately after closing the cock and while 
the drum is still being moved by the engine, for the reason 
that there is not so much liability of getting the atmos¬ 
pheric line too high owing to the presence of a slight 
pressure of steam remaining under the indicator piston 
for a second or two just after closing the cock; also the 
line drawn by hand will be longer than one drawn while 
the drum is moved by the motion of the engine and will 
therefore be more readily distinguished from the line of 
back pressure. 






THE INDICATOR—PRINCIPLES OF INDICATOR 28d 

Ques. 647.—What other details should jc observed in 
the taking of indicator diagrams? 

Ans.—As soon as the diagrams are taken the following 
data should be noted upon them: The end of the cylinder, 
whether head or crank; boiler-pressure, and time when 
taken. Other data can be added afterwards. 

Ques. 648.—What needed changes in the cut-off of a 
Corliss engine, as shown by a diagram, may be made while 
the engine is running? 

Ans.—If the engine is an automatic cut-off of the 
Corliss type and the point of cut-off on one end does not 
coincide with the other, the difference can generally be 
adjusted while the engine is running by changing the 
length of the rods extending from the governor to the 
tripping device. These rods are, or should be fitted with 
right and left threads on the ends for this purpose. Any 
changes in the valves, such as giving them more lead, 
compression, etc., and which necessitates changing the 
length of the reach rods connecting them with the wrist 
plate, will have to be made while the engine is stopped, 
although with slow-speed engines and the exercise of 
caution it is possible to make alterations in these rods 
while the engine is running. 

Ques. 649.—What important details will a truthful 
indicator diagram show? 

Ans.—First, the pressure of the steam against the 
piston of the engine at any point in the stroke during a 
complete revolution; second, diagrams from a condensing 
engine show the amount of vacuum that is being main¬ 
tained in the condenser, measured from the line of perfect 

t 







286 


QUESTIONS AND ANSWERS 


vacuum; third, the point of cut-off is clearly shown, also 
the point in the return stroke at which compression 
begins; fourth, the expansion curve, and how near it 
approaches the theoretical expansion curve; fifth, any 
fault in the setting of the valves is clearly shown on 
the diagram; sixth, diagrams taken from the different 
cylinders of a compound or stage expansion engine may 
be combined in such a manner as to show whether or not 
the cylinders are properly proportioned, and whether the 
steam is being distributed correctly. 

Ques. 650.—What is absolute pressure? 

Ans.—Pressure reckoned from a perfect vacuum. It 
equals the boiler-pressure plus the atmospheric pres¬ 
sure. 

Ques. 651 —What is boiler-pressure or gauge-pres¬ 
sure? 

Ans.—Pressure above the atmospheric pressure as 
shown by the steam gauge. 

Ques. 652.—What is initial pressure? 

Ans.—Pressure in the cylinder at the beginning of the 
stroke. 

Ques. 653.—What is meant by terminal pressure (T. 

P.)? 

Ans.—The pressure that would exist in the cylinder 
at the end of the stroke provided the exhaust valve did 
not open until the stroke was entirely completed. It 
may be graphically illustrated on the diagram by extend¬ 
ing the expansion curve by hand to the end of the stroke. 
It is found theoretically by dividing the pressure at point 
of cut-off by the ratio of expansion. Thus, absolute 














THE INDICATOR—PRINCIPLES OF INDICATOR 287 

pressure at cut-off —100 pounds, ratio of expansion = 5; 
then 100"^"5 — 20 pounds, absolute terminal pressure. 

Ques. 654.—What is mean effective pressure (M. E. 

p.)? 

Ans.—The average pressure acting upon the piston 
througnout the stroke minus the back pressure. 

Ques. 655.—What is back pressure? 

Ans.—Pressure which tends to retard the forward 
stroke of the piston. Indicated on the diagram from a 
non-condensing engine by the height of the back pressure 
line above the atmospheric line. In a condensing engine 
the degree of back pressure is shown by the height of the 
back pressure line above an imaginary line representing the 
pressure in the condenser corresponding to the degree 
of vacuum in inches, as shown by the vacuum gauge. 

Ques. 656.—What is total or absolute back pressure? 

Ans.—Total or absolute back pressure, in either a 
condensing or non-condensing engine, is that indicated 
on the diagram by the height of the line of back pressure 
above the line of perfect vacuum. 

Ques. 657.—How is the line of perfect vacuum drawn 
on an indicator diagram? 

Ans.—The line of perfect vacuum is drawn parallel 
with the atmospheric line and at a distance below the 
latter, representing 14.7 pounds, as measured by the scale 
corresponding to the spring that was used in taking the 
diagram. Different scales are supplied for the different 
springs used. 

Ques. 658.—What is meant by ratio of expansion? 

Ans.—The Drooortion that the volume of steam in the 



288 


QUESTIONS AND ANSWERS 


cylinder at point of release bears to the volume at cut-off. 
Thus, if the point of cut-off is at one-fifth of the stroke, 
and release does not take place until the end of the stroke, 
the ratio of expansion, or in other words, the number of 
expansions, is 5. When the T. P. is known the ratio of 
expansion may be found by dividing the initial pressure 
by the T. P. 

Ques. 659.—What h neart by wire drawing? 

Ans.—When through insufficiency of valve opening, 
contracted ports or throttling governor, the steam is 
prevented from following up the piston at full initial 
pressure until the point of cut-off is reached, it is said to 
be wire drawn. It is indicated on the diagram by a 
gradual inclination downwards of the steam line from 
the admission line to the point of cut-off. Too small a 
steam pipe from boiler to engine will also cause wire 
drawing and fall of pressure. 

Ques. 660.—What is condenser pressure? 

Ans.—Condenser pressure may be defined as the pres¬ 
sure existing in the condenser of an engine, caused by 
the lack of a perfect vacuum. As, for instance, with a \ 
vacuum of 25 inches there will still remain the pressure 5 
due to the 5 inches which is lacking. This will be about t 
2.5 pounds. 

Ques. 661.—What is absolute zero? 

Ans.—Absolute zero has been fixed by calcula¬ 
tion at 461.2 degrees below the zero of the Fahrenheit 
scale. 

Ques. 662.—What is piston displacement? 

Ans.—The space or volume swept through by the * 





THE INDICATOR—PRINCIPLES OF INDICATOR 289 

piston in a single stroke. Found by multiplying the 
area of piston by length of stroke. 

Ques. 663.—What is piston clearance? 

Ans.—The distance between the piston and cylinder 
head when the piston is at the end of the stroke. 

Ques. 664.—What is steam clearance, ordinarily 
termed clearance? 

Ans.—The space between the piston at the end of the 
stroke and the valve face. It is reckoned in per cent 
}f the total piston displacement. 

Ques. 665.—What is the meaning of the expression 
lorse-power as applied to a steam-engine? 

Ans.—33,000 pounds raised one foot high in one 
minute of time. 

Ques. 666.—What is indicated horse-power (I. H. P.)? 

Ans.—The horse-power as shown by the indicator 
liagram. It is found as follows: Area of piston in 
quare inchesXM. E. P. X piston speed in feet-^33,000. 

Ques. 667.—What is meant by the term piston speed? 

Ans.—The distance in feet traveled by the piston in 
ne minute. It is the product of twice the length of 
i troke expressed in feet multiplied by the number of 
: evolutions per minute. 

Ques. 668.—What is net horse-power? 

Ans.—I. H. P. minus the friction of the engine 

Ques. 669.—What is compression? 

Ans,—The action of the piston as it nears the end of 
^ie stroke, in reducing the volume and raising the pres¬ 
sure of the steam retained in the cylinder ahead of the 
! iston by the closing of the exhaust valve. 













290 


QUESTIONS AND ANSWERS 


Ques. 670.—What is Boyle’s law of expanding gases? 

A ns.—“The pressure of a gas at a constant tempera¬ 
ture varies inversely as the space it occupies. Thus, 
if a given volume of gas is confined at a pressure of 
50 pounds per square inch and it is allowed to expand to 
twice its volume, the pressure will fall to 25 pounds per 
square inch. 

Ques. 671.—What is an adiabatic curve? 

Ans.—A curve representing the expansion of a gas 
which loses no heat while expanding. Sometimes called 
the curve of no transmission. 

Ques. 672.—What is an isothermal curve? 

Ans.—A curve representing the expansion of a gas 
having a constant temperature but partially influenced 
by moisture, causing a variation in pressure according 
to the degree of moisture or saturation. It is also called 
the theoretical expansion curve. 

Ques. 673.—What is the expansion curve? 

Ans.—The curve traced upon the diagram by the 
indicator pencil showing the actual expansion of the steam 
in the cylinder. 

Ques. 674.—What is power? 

Ans.—The rate of doing work, or the number of foot 
pounds exerted in a given time. 

Ques. 675.—What is the unit of work? 

Ans.—The foot pound, or the raising of one pound 
weight one foot high. 

Ques. 676.—Define the first law of motion. 

Ans.—All bodies continue either in a state of rest oi 
of uniform motion in a straight line, except in so far aj 






THE INDICATOR-PRINCIPLES OF INDICATOR 291 

they may be compelled by impressed forces to change that 
Mate. 

Ques. 677.—What is work? 

Ans.—Mechanical force or pressure can not be con¬ 
sidered as work unless it is exerted upon a body and 
causes that body to move through space. The product 
of the pressure multiplied by the distance passed through 
and the time thus occupied is work. 

Ques. 678.—What is momentum? 

Ans.—Force possessed by bodies in motion, or the 
product of mass and density. 

Ques. 679.—What is the meaning of the word dynam¬ 
ics? 

Ans.—The science of moving powers or of matter in 
motion, or of the motion of bodies that mutually act upon 
2 ach other. 

Ques. 680.—What is force? 

Ans.—That which alters the motion of a body or puts 
n motion a body that was at rest. 

Ques. 681.—What is the maximum theoretical duty 
)f steam? 

Ans.—The maximum theoretical duty of steam is the 
product of the mechanical eqjijivalent of heat, viz., 778 
oot pounds multiplied by the total heat units in a 
>ound of steam. Thus, in one pound of steam at 212 
legrees reckoned from 32 degrees the total heat equals 
,146.6 heat units. Then 778X1,146.6 = 892,054.8 foot 
>ounds=maximum duty. 

Ques. 682.—What is steam efficiency? 

Ans.—Steam efficiency ma.v be expressed as follows; 






292 


QUESTIONS AND ANSWERS 


Heat converted into useful work 


and maximum efficiency 


Heat expended 
can only be attained by using steam at as high an initial 
pressure as is consistent with safety, and at as large a 
ratio of expansion as possible. 

Ques. 683.—What is meant by the term efficiency of 
the plant as a whole? 

Ans.—Efficiency of the plant as a whole includes 
boiler and engine efficiency, and is to be figured upon the 

, . f Heat converted into useful work 

aSIS ° Calorific or heat value of fuel 

Ques. 684.—What is the horse-power constant of ar 
engine? 

Ans.—The horse-power constant of an engine is found 
by multiplying the area of the piston in square inches b] 
the speed of the piston in feet per minute and dividing 
the product by 33,000. It is the power the engine woul< 
develop with one pound mean effective pressure. To find 
the horse-power of the engine, multiply the M. E. P. of 
the diagram by this constant. 

Ques. 685.—What is meant by the expression stearv 
consumption per horse-power per hour? 

Ans.—The weight in pounds of steam exhausted intc 
the atmosphere or into the condenser in one hour divided 
by the horse-power developed. It is determined from the 
diagram by selecting a point in the expansion curve jusl 
previous to the opening of the exhaust-valve anc 
measuring the absolute pressure at that point. Then th< 
piston displacement up to the point selected, plus 
the clearance space, expressed in cubic feet, wil 













THE INDICATOR—PRINCIPLES OF INDICATOR 293 

give the volume of steam in the cylinder, which multiplied 
by the weight per cubic foot of steam at the pressure 
as measured will give the weight of steam consumed during 
one stroke. From this should be deducted the steam 
saved by compression as shown by the diagram, in order 
to get a true measure of the economy of the engine. 
Having thus determined the weight of steam consumed 
• for one stroke, multiply it by twice the number of 
! strokes per minute and by 60, which will give the total 
weight consumed per hour. This divided by the horse¬ 
power will give the rate per horse-power per hour. 

Ques. 686.—What is cylinder condensation and 
reevaporation? 

Ans.—When the exhaust-valve opens to permit the 
exit of the steam there is a perceptible cooling of the 
walls of the cylinder, especially in condensing engines 
when a high vacuum is maintained. This results in 
more or less condensation of the live steam admitted by 
/the opening of the steam-valve; but if the exhaust- 
Ivalve is caused to close at the proper time so 
las to retain a portion of the steam to be compressed by 
the piston on the return stroke, a considerable poition 
nf the water caused by condensation will be reevaporated 
into steam by the heat and consequent rise in pressure 
:aused by compression. 

Ques. 687.—What are ordinates, as applied to indi¬ 
cator diagrams? 

Ans.—Parallel lines drawn at equal distances apart 
across the face of the diagram and perpendicular to the 
atmospheric line. They serve as a guide to facilitate the 










294 


QUESTIONS AND ANSWERS 


measurement of the average forward pressure through¬ 
out the stroke, or the pressure at any point of the stroke 
if desired. 

Ques. 688.—What is a throttling governor? 

Ans.—A governor that is used to regulate the speed 
of engines having a fixed cut-off. The governor controls 
the position of a valve in the steam-pipe, opening or clos- 



Fig. 180. Illustrating the Process of Obtaining the Mean Effective 

Pressure by Means of Ordinates. 


ing it according as the engine needs more or less steam in 
order to maintain a regular speed. 

Ques. 689.—What is an automatic or variable cut¬ 
off engine? 

Ans.—In engines of this type the full boiler pressure 
is constantly in the valve chest and the speed of the 
engine is regulated by the governor controlling the point 
of cut-off, causing it to take place earlier or later 
according as the load on the engine is lighter or heavier. 

















THE INDICATOR-PRINCIPLES OF INDICATOR 295 

Ques. 690.—What is a fixed cut-off? 

1 

Ans.—This term is applied to engines in which the 
point of cut-off remains the same regardless of the load, 
the speed being regulated by a throttling governor. 

Ques. 691.—What is an adjustable cut-off? 

Ans.—One in which the point of cut-off may be regu¬ 
lated or adjusted by hand by means of a hand wheel and 
screw attached to the valve stem, the supply of steam 
being regulated by a throttling governor. 

Ques. 692.—What is an isochronal or shaft governor? 



Fig. 181. Indicator Diagram Taken from a Condensing Engine. 


A, atmospheric line. V, line of perfect vacuum. B to D. admission line. 
D to E, steam line. E, point of cut-off. E to F, expansion line. F to G, ex¬ 
haust. G to C, line of back pressure; and from C to B shows compression. 


Ans.—This device in which the centrifugal and cen¬ 
tripetal forces are utilized, as in the fly-ball governor, is 
generally applied to automatic cut-off engines having 
reciprocating or slide valves. It is attached to the crank 
shaft and its function is to change the position of the 
eccentric, which is free to move across the shaft within 
certain prescribed limits, but is at the same time attached 
to the governor. The angular advance of the eccentric 
is thus increased or diminished; in fact is entirely under 









296 


QUESTIONS AND ANSWERS 


the control of the governor, and cut-off occurs earlier or 
later according to the demands of the load on the 
engine. 

Ques. 693.—If the valves of an engine are properly 
adjusted and the distribution of the steam is approxi¬ 
mately correct, what particular features should character¬ 
ize an indicator diagram taken from it? 

Ans.—First, the admission line at the beginning of the 
stroke should be perpendicular to the atmospheric line; 
second, the steam line, as it is called, extending from the 
beginning of the stroke to the point of cut-off, should be 



Fig. 182. Diagram Showing Insufficient Lead. 




parallel with the atmospheric line; third, the point of 


cut-off should be sharply defined; fourth, the expansion 
' curve, extending from the point of cut-off to the point of 
release, should conform as near as possible with the 
isothermal curve, which can easily be applied to any dia¬ 
gram; fifth, the exhaust line, extending from point of 
release to that point in the return stroke where compres¬ 
sion begins, should be parallel with and practically coin¬ 
cident with the atmospheric line, if the engine is 
non-condensing, or if the engine be a condensing engine. 











THE INDICATOR-PRINCIPLES OF INDICATOR 297 

this line should approach within a few pounds of the line 
}f perfect vacuum. 

Ques. 694.—If the admission line inclines inward 
from the perpendicular, what defect in the valve setting 
s indicated? 

Ans.—Insufficient lead. 

Ques. 695.—How is wire drawing of the steam 
ietected by the indicator diagram? 

Ans.—By the downward inclination of the steam line 
toward the point of cut-off. 



_ __— V 

Fig. 183. Diagram Showing Effects of Wire Drawing the Steam. 


Ques. 696.—What is a very necessary factor in the 
calculation of the horse-power of an engine as shown by 
a diagram taken from it? 

Ans.—The mean effective pressure. 

Ques. 697.—How is the M. E. P. of a diagram ascer¬ 
tained? 

Ans.—There are two methods commonly used. First* 
bv means of ordinates, and secondly, by the use of the 
planimeter. 















298 


QUESTIONS AND ANSWERS 


Ques. 698 .—Describe the method of finding the M. 
E.. P. by ordinates. 

Ans.—The process consists in drawing any convenient 
number of vertical lines perpendicular to the atmospheric 
line across the face of the diagram, spacing them equally, 
with the exception of the two end spaces, which should 
be one-half the width of the others, for the reason that 
the ordinates stand for the centers of equal spaces. This 
is an important matter, and should be thoroughly under- 


•m 

SS 

Z 

•9 

•ot 

8 

7 



TfTjr. n.E.p 

Fig. 184. Finding M. E. P. 




stood, because if the spaces are all made of equal width, 
and measurements are taken on the ordinates, the results.! 
will be incorrect, especially in the case of high initial pres¬ 
sure and early cut-off, following which the steam undergoes 
great changes. If the spaces are all made equal, the meas¬ 
urements will require to be taken in the middle of them, and 
errors are liable to occur, whereas if spaced as before 
described, the measurements can be made on the ordinates, 
which is much more convenient and will insure correct 
results. Any number of ordinates can be drawn, but ten 





















THE INDICATOR-PRINCIPLES OF INDICATOR 299 

is the most convenient and is amply sufficient, except in 
case the diagram is excessively long. 

Ques. 699.—Having succeeded in drawing the ordi- 
: nates across the face of the diagram, what is the next step? 

Ans.—The pressure represented by each line is meas- 
1 ured from the exhaust line to the steam line, and so on. 



Fig. 185. Peanimeter. 


along the expansion curve throughout the length of the 
diagram, using for this purpose the scale adapted to the 
fpring used, and having thus obtained measurements on 
each line, add all together and divide the sum total by 
the number of lines, which will give the mean forward 
pressure. To obtain the mean effective pressure, deduct 
the back pressure, which is represented by the distance 


















300 


QUESTIONS AND ANSWERS 


of the exhaust line above the atmospheric line in a non¬ 
condensing engine, and in a condensing engine the back 
pressure is measured from the line of perfect vacuum. 



Fig. 186 . Coffin Averager or Peanimeter. 


Ques. 700.—What is a planimeter? 

^ns.—The planimeter is an instrument which will 




















































































































THE INDICATOR-PRINCIPLES OF INDICATOR 301 

. accurately measure the area of any plane surface, no 
; matter how irregular the outline or boundary line is. 

Ques. 701.—What is the main requirement in ascer¬ 
taining the M. E. P. of a diagram? 

Ans.—The prime requisite m making power calcula¬ 
tions from indicator diagrams is to obtain the average 
height or width of the diagram, supposing it were reduced 
to a plain parallelogram instead of the irregular figure 
which it is. 

Ques. 702.—What advantage is gained by using the 
planimeter in measuring diagrams? 

Ans.—It shows at once the area of the diagram in 
square inches and decimal fractions of a square inch, and 
when the area is thus known it is an easy matter to obtain 
the average height by simply dividing the area in inches 
by the length of the diagram in inches. Having ascer¬ 
tained the average height of the diagram in inches or 
fractions of an inch the mean or average pressure is 
found by multiplying the height by the scale. Or the 
process may be made still more simple by first multiplying 
the area, as shown by the planimeter in square inches and 
decimals of an inch, by the scale and dividing the product 
by the length of the diagram in inches. The result will 
be the same as before, and troublesome fractions will be 
avoided. 

Ques. 703.—Having obtained the M. E. P., as shown 
by the diagram, how may the horse-power developed by 
the engine be ascertained? 

Ans.—The area of the piston (minus one-half the are* 
of rod) multiplied by the M. E. P., as shown by the dia- 





302 


QUESTIONS AND ANSWERS 


gram, and this product multiplied by the number of fee 
traveled by the piston per minute (piston speed) will giv< 
the number of foot pounds of work done by the engin< 
each minute, and if this product be divided by 33,000 
the quotient will be the indicated horse-power (I. H. P.] 
developed by the engine. 

Ques. 704.—Mention two important factors in calcu¬ 
lations of steam consumption. 

Ans.—In calculating the steam consumption of ar 
engine, two very important factors must not be lost sighi 
of, viz., clearance and compression. Especially is this 
the case in regard to clearance when there is little or nc 
compression, for the reason that the steam required to fil 
the clearance space at each stroke of the engine is prac¬ 
tically wasted, and all of it passes into the atmosphere oi 
the condenser, as the case may be, without having done 
any useful work except to merely fill the space devoted tc 
clearance. On the other hand, if the exhaust valve is 
closed before the piston completes the return stroke, the 
steam then remaining in the cylinder will be compressed 
into the clearance space and can be deducted from the 
total volume which, without compression, would have beer« 
exhausted at the terminal pressure. 

Ques. 705.—When, owing to light load and earty 
cut-off, the expansion curve drops below the line of back 
pressure, how must the area of the diagram be calculated: 

Ans.—The area of the loop below the back pressure 
line must be subtracted from the remainder of the diagram. 
If the planimeter is used, the instrument will make the sub¬ 
traction automatically, but if the diagram is divided into 





THE INDICATOR-PRINCIPLES OF INDICATOR 303 


barts by ordinates, the pressure shown by the ordinates in 
>:he lower loop must be subtracted from that shown by 
: :he loop above the back pressure line in order to ascertain 
idle M. E. P. or average pressure. 

Ques. 706.—What is meant by the adiabatic curve? 


S 



Fig. 187. 


The dotted line R C shows what the true adiabatic curve would be on the 
liagram, provided it could be realized. 


Ans.—If it were possible to so protect or insulate the 
;ylinder of a steam engine that there would be absolutely 
10 transmission of heat either to or from the steam dur¬ 
ing expansion, a true adiabatic curve or “curve of no 
transmission” might be obtained. The closer the actual 
expansion curve of a diagram conforms to such a curve, 
the higher will be the efficiency of the engine as a 
machine for converting heat into work. 


























CHAPTER X 

THE STEAM TURBINE—FUNDAMENTAL PRINCIPLES 

Ques. 707.—What are the basic principles governing 
the action of steam turbines? 

Ans.—There are wo fundamental principles upon 
which all steam turbines operate, viz., reaction and 
impulse. In some types of turbines the reaction principle 
alone is utilized, and in others the impulse, while in still 
others, and probably the most successful ones, both 
principles are combined. 

Ques. 708.—In what general direction does the steam 
flow when used in a turbine? 

Ans.—Parallel with the shaft or rotor, and also in a 
screw-like direction around it. This definition does not 
apply, however, to turbines of the purely impulse type, 
like the De Laval, for instance. 

Ques. 709.—What causes the rotor to revolve? 

Ans.—The action of the steam, coming, as it does, 
with tremendous velocity and great force against the 
small buckets or vanes with which the rotor is fitted, 
causes it to revolve, and as there is a continuous current 

of steam passing into the cylinder, the motion is continu¬ 
ous. 

Ques. 710. What law of turbo-mechanics governs 
the relation of bucket-speed, and fluid or steam speed? ~2 

Ans.—For purely impulse-wheels, bucket-speed equals 
one-half of jet-speed. For reaction wheels, bucket-speed 
equals jet-speed. 


304 








STEAM TURBINE-FUNDAMENTAL PRINCIPLES 305 


Ques. 711—With what velocity would steam of 100 
pounds pressure discharge into a vacuum of 28 inches? 

Ans.—The theoretical velocity would be 3,860 feet per 
second. 

Ques. 712.—What amount of energy would a cubic 
foot of steam under 100 pounds pressure exert if allowed 
I to discharge into a vacuum of 28 inches? 

Ans.—59,900 foot pounds. 

Ques. *713.—Does the steam impinge against the first 
•ows or sections of buckets at full pressure? 

Ans.—In turbines of the Parsons type, the initial 
pressure of the steam is practically boiler-pressure, but 
t gradually falls as it p"_ses on through the cylinder, 
vhich becomes larger in diameter as the exhaust end is 
ipproached. In other types of turbines, the steam is 
idmitted to and directed against the blades or buckets, 
hrough expanding nozzles, and by the time it strikes the 
irst stage, or section of moving vanes, the pressure has 
alien to one-third or less of the original boiler-pressure, 
>ut the velocity is very great. 

Ques. 714.—In what particular respect does the steam 

i 

urbine appear to possess an advantage over the recipro¬ 
cating engine, in the use of steam? 

Ans.—The turbine, if designed along correct lines, 
is capable of utilizing in the highest degree one of the 
nost valuable properties of steam, viz., velocity. 

Ques. 715.—Give an example of the great increase in 

he amount of work performed by an agent when velocity 

i 

s one of the factors made use of. 

Ans.—Suppose that a man is standing within arm’s 




306 


QUESTIONS AND ANSWERS 


length of a heavy plate-glass window and that he holds in 
his hand an iron ball weighing 10 pounds. Suppose the 
man should place the ball against the glass and press the 
same there with all the energy he is capable of exerting.! 
He would make very little, if any, impression upon the! 
glass. But suppose that he should walk away from the! 
^window a distance of 20 feet, and then exert the same 
amount of energy in throwing the ball against the glass, 
a different result would ensue. The velocity with which 
the ball would impinge against the surface of the glass 
would no doubt ruin the window. Now, notwithstanding 
the fact that weight, energy, and time involved were 
exactly the same in both instances, yet a much larger 
amount of work was performed in the latter case, owing 
to the added force imparted to the ball by the velocity with 
which it impinged against the glass. 

Ques. 716.—Describe the construction and action of 
the De Laval steam turbine. 

Ans.—The De Laval steam turbine is termed by its 
builders a high-speed rotary steam-engine. It has but a 
single wheel, fitted with vanes or buckets of such curva¬ 
ture as has been found to be best adapted for receiving 
the impulse of the steam-jet. There are no stationary or 
guide-blades, the angular position of the nozzles giving 
direction to the jet. The nozzles are placed at an angle 
of 20 degrees to the plane of motion of the buckets, j 
The heat energy in the steam is practically devoted to 
the production of velocity in the expanding or divergent 
nozzle, and the velocity thus attained by the issuing jet 
of steam is about 4,000 feet per second. To attain the 








STEAM TURBINE—FUNDAMENTAL PRINCIPLES 307 

naximum of efficiency, the buckets attached to the 
periphery of the wheel against which this jet impinges 
;hould have a speed of about 1,900 feet per second, but, 
>wing to the difficulty of producing a material for the 
vheel strong enough to withstand the strains induced by 



Fig. 188 . The De Laval Turbine Wheel and Nozzles. 


ich a high speed, it has been found necessary to limit 
le peripheral speed to 1,200 or 1,300 feet per second. 

Ques. 717.—Describe the action of the steam in its 
issage through the De Laval diverging nozzle. 

Ans.—It is well known that in a correctly designed 
)zzle the adiabatic expansion of the steam from max- 










308 


QUESTIONS AND ANSWERS 




imum to minimum pressure will convert the entire static 
energy of the steam into kinetic. Theoretically this is 
what occurs in the De Laval nozzle. The expanding steam 


acquires great velocity, and the energy of the jet of steam 



issuing from the nozzle is equal to the amount of energy 
that would be developed if an equal volume of steam wen 
allowed to adiabatically expand behind the piston of ; 
reciprocating engine, a condition, however, which foi 
obvious reasons has never yet been attained in practice 


































STEAM TURBINE-FUNDAMENTAL PRINCIPLES 309 

vith the reciprocating engine. But with the divergent 
lozzle the conditions are different. 

Ques. 718.—What is the usual speed of the De Laval 
team-turbine wheel? 

Ans.—From 10,000 to 30,000 revolutions per minute, 
ccording to the size of the machine. 

Ques. 719.—How are the difficulties attending such 
igh velocities overcome? 

Ans.—By the long, flexible shaft and the ball and 
ocket type of bearings, which allow of a slight flexure 
f the shaft in order that the wheel may revolve about its 
enter of gravity rather than the geometrical center or 
enter of position. All high-speed parts of the machine 
re made of forged nickel steel of great tensile strength. 

Ques. 720.—How is the speed of the De Laval 
irbine-wheel and shaft reduced and transmitted for 
ractical purposes? 

Ans.—By a pair of very perfectly cut spiral gears, 
sually made 10 to 1. These gear-wheels are made of 
olid cast steel, or of cast iron with steel rims pressed on. 
he teeth in two rows are set at an angle of 90 degrees to 
ich other. This arrangement insures smooth running 
(id at the same time checks any tendency of the shaft 
wards end-thrust, thus dispensing with a thrust bearing. 

Ques. 721.—How are the buckets made and fitted to 
te De Laval wheel? 

A ns.—The buckets are drop-forged and made with a 
ilb shank, fitted in slots, that are milled in the rim of 
le wheel. 

Ques. 722.—How many buckets are there? 






310 


QUESTIONS 


AND ANSWERS 


V ' I 


Ans.—The number of buckets varies according to th 


capacity of the machine. There are about 350 bucket 



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up to the present time. 









-'TEAM TURBINE-FUNDAMENTAL PRINCIPLES 311 

i Ques. 723.—IIow many of the diverging nozzles are 
I fitted to each wheel? 

Ans.—The number of these nozzles depends upon the 
size ot the machine, ranging from one to fifteen. They 
are generally fitted with shut-off valves by which one or 
more nozzles can be cut out when the load is light. This 



Fig. 191. Working Parts of the De Laval Steam Turbine. 


V.—Turbine shaft. 

3.—Turbine wheel. 

2 . —Pinion. 

D.—Pinion bearing, two parts. 
5.—Pinion bearing, two parts. 

7 .—Wheel bearing with spring. 

3. —Flexible bearing. 

L—Gear wheel. 


I. —Gear wheel shaft. 

J. —Gear wheel bearing, two parts. 

K. —Oil ring. 

L. —Gear wheel bearing in position. 

M. —Coupling. 

N. —Centrifugal governor. 

O. —Gland adjusting nut. 

P. —Adjusting nut for flexible bearing 


*enders it possible to use steam at boner-pressure, no 
natter how small the volume required for the load. This 
s a matter of great importance, especially where the load 
varies considerably, as, for instance, there are plants in 
vhich during certain hours of the day a 300 horse-power 
nachine may be taxed to its utmost capacity and during 






312 


QUESTIONS AND ANSWERS 


certain other hours the load on the same machine maj 
drop to 50 horse-power. In such cases the number oi 
nozzles in action may be reduced by closing the shut-ofi 
valves until the required volume of steam is admitted tc 
the wheel. This adds to the economy of the machine 
After passing through the nozzles, the steam, as elsewhere 
explained, is now completely expanded, and in impinging 
on the buckets its kinetic energy is transferred to the 
turbine wheel. Leaving the buckets, the steam now 
passes into the exhaust-chamber, and out through the 
exhaust-opening, to the condenser or atmosphere, as the 
case may be. 

Ques. 724.—How is the speed of this turbine regu¬ 
lated ? 

Ans.—The governor is of the centrifugal type, 
although differing greatly in detail from the ordinary 
fly-ball governor. It is connected directly to the end of 
the gear-wheel shaft. 

Ques. 725.—Describe the methods of lubricating the 
bearings on the De Laval turbine. 

Ans.—The main shaft and dynamo bearings are ring- 
oiling. The high-speed bearings on the turbine shaft are 
fed by gravity from an oil-reservoir, and the drip-oil is 
collected in the base and may be filtered and used again. 

Ques. 726.—What can be said regarding the steam- 
consumption of this turbine? 

Ans.—Efficiency tests of the De Laval turbine show 
a high economy in steam-consumption, as, for instance, a 
test made by Messrs. Dean and Main, of Boston, Mass., 
on a 300 horse-power turbine, using saturated steam at 








STEAM TURBINE-FUNDAMENTAL PRINCIPLES 313 


about 200 pounds pressure per square inch and develop¬ 
ing 333 brake horse-power, showed a steam-consumption 
of 15.17 pounds per brake horse-power, and the same 
1 machine, when supplied with superheated steam and 
carrying a load of 352 brake horse-power, consumed but 



Two weights B are pivoted on knife edges A with hardened pins C. bearing 
on the spring seat D. E is the governor body fitted in the end of the gear wheel 
shaft K and has seats milled for the knife edges A. It is afterwards reduced m 
diameter to pass inside of the weights and its outer end is threaded to receive 
the adjusting nut I. by means of which the tension of the spring, and through 
this the speed of the turbine, is adjusted. When the speed accelerates, the 
weights, affected by centrifugal force, tend to spread apart, and pressing on the 
spring seat at D push the governor pin G to the right, thus actuating the bell 
crank L and cutting off a part of the flow of steam. 


13.94 pounds per brake horse-power. These results 
compare most favorably with those of the highest type of 


reciprocating engines. 

Ques. 727.—Since the steam is used in but a single 











































































V. 

314 QUESTIONS AND ANSWERS 

stage or section of buckets in the De Laval turbine, why 
such good economy in the use of steam? 

Ans.—The static energy in the steam as it enters the 
nozzles is converted into kinetic energy by its passage 
through the divergent nozzles, and the result is a greatly 
increased volume of steam leaving the nozzles at a tre¬ 
mendous velocity, but at a greatly reduced pressure— 
practically exhaust pressure—impinging against the 
buckets of the turbine wheel and thus causing it to 
revolve. 

Table No. 11 

Capacities and Speed of De Laval Turbines 


Horse Power. 

Revolutions 
Turbine Shaft. 

Revolutions 
Main Shaft. 

Approximate 

Weight, 

Pounds. 

5 

30,000 

3,000 

330 

10 

24,000 

2,400 

650 

20 

20,000 

2,000 

1,250 

75 

16,400 

1,500 

5,000 

110 

13,000 

1,200 

8,000 

225 

11,060 

900 

15,000 

300 

10,500 

900 

20,000 


Ques. 728.—Describe in general terms the Curtis 
steam-turbine. 

Ans.—The Curtis turbine is built by the General 
Electric Company at their works in Schenectady, N. Y., 
and Lynn, Mass. The larger sizes are of the vertical 
type, and those of small capacity are horizontal. In the 
vertical type the revolving parts are set upon a vertical 
chaft, the diameter of the shaft corresponding to the size 
of the machine. The shaft is supported by and runs 
upon a step-bearing at the bottom. This step-bearing 















STEAM TURBINE-FUNDAMENTAL PRINCIPLES 315 


consists of two cylindrical cast-iron plates bearing upon 
each other and having a central recess between them into 
which lubricating oil is forced under pressure by a steam 
or electrically driven pump, the oil passing up from 



Fig. 193. 5.000 K. W. Curtis Steam Turbtne Direct Connected to 5,000 
K. W. Three-phase Alternating Current Generator. 


beneath. A weighted accumulator is sometimes installed 
in connection with the oil pipe as a convenient device for 
governing the step-bearing pumps, and also as a safety 
device in case the pumps should fail, but it is seldom 
required f^r the latter purpose, as 1 he step-bearing pumps 













316 


QUESTIONS AND ANSWERS 


have proven, after a long service in a number of cases, 
to be reliable. The vertical shaft is also held in place and 
kept steady by three sleeve bearings, one just above the 
step, one between the turbine and generator, and the 
other near the top. These guide bearings are lubricated 
by a standard gravity feed system. It is apparent that 
the amount of friction in the machine is very small, and 
as there is no end-thrust caused by the action of the 
steam, the relation between the revolving and stationary 
blades may be maintained accurately. As a consequence, 
therefore, the clearances are reduced to the minimum. 
The Curtis turbine is divided into two or more stages, 
and each stage has one, two or more sets of revolving 
blades bolted upon the peripheries of wheels keyed to the 
shaft. There are also the corresponding sets of station¬ 
ary blades, bolted to the inner walls of the cylinder or 
casing. 

Ques. 729.—What is the diameter of the vertical shaft 
for a 5,000 kilowatt turbine and dynamo? 

Ans.—Fourteen inches. 

Ques. 730.—How is the heat energy in the steam 
imparted to the wheel of the Curtis turbine? 

Ans.—Both by impulse and reaction. The steam is 
admitted through expanding nozzles in which nearly all of 
the expansive force of the steam is transformed into the 
force of velocity. The steam is caused to pass through 
one, two, or more stages of moving elements, each stage 
having its own set of expanding nozzles, each succeeding 
set of nozzles being greater in number and of larger area 
than the preceding set. The ratio of expansion within 





STEAM TURBINE-FUNDAMENTAL PRINCIPLES 317 


these nozzles depends upon the number of stages, as, for 
instance, in a two-stage machine the steam enters the 
initial set of nozzles at boiler-pressure, say 180 pounds. 
It leaves these nozzles and enters the first set of moving 
blades at a pressure of about 15 pounds, from which it 
further expands to atmospheric pressure in passing 



Fig.194. 


One Stage oe a 500 K. W. Curtis Steam Turbine in Course oe 
Construction. 


through the wheels and intermediates. From the pres¬ 
sure in the first stage the steam again expands through 
I the larger area of the second stage nozzles to a pressure 
slightly greater than the condenser vacuum at the 
entrance to the second set of moving blades, against 
which it now impinges and passes through, still doing 
work, due to velocity and mass. From this stage the 
















31S 


QUESTIONS AND ANSWERS 


steam passes to the condenser. If the turbine is a four 
stage machine and the initial pressure is 180 pounds, th 
pressure at the different stages would be distributed i 


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Fig. 195. 


Diagram of the nozzles, moving blades and stationary blades of a two-stae 
vT U ^ 1S s * e . am t u j*bme. 1 he steam enters the nozzle openings at the top, controlled 
by the valves shown, two of the valves are open, and the course of the steam 
through the first stage is indicated by the arrows. 


about the following manner: Initial pressure, 
pounds; fi-st stage, 50 pounds: second stage, 5 pour 












































































-STEAM TURBINE-FUNDAMENTAL PRINCIPLES 319 

third stage, partial vacuum, and fourth stage, condenser 
vacuum. 

Ques. 731.—What are the diameters of the wheels? 

Ans.—The diameters of the wheels vary according to 
the size of the machine, that of a 5,000 kilowatt unit being 
13 feet. 

Ques. 732.—What amount of clearance is there be^ 
tween the revolving and stationary blades? 

Ans.—The clearance between the revolving and sta- 
i tionary blades is from to tV inch, thus reducing the 
wastage of steam to a very low percentage. 

Ques. 733.—Describe the action of the steam in a 
two-stage Curtis turbine. 

Ans.—The steam enters the nozzle openings at the top 
through valves that are controlled by the governor, 
j After passing successively through the different sets of 
moving blades and stationary blades in the first stage, the 
steam passes into the second steam-chest. The flow of 
steam from this chamber to the second stage of buckets 
is also controlled by valves, but the function of these 
valves is not in the line of speed-regulation, but for the 
purpose of limiting the pressure in the stage-chambers, 
in a manner somewhat similar to the control of the 
receiver pressure in a two-cylinder or three-cylinder 
compound reciprocating engine. The valves controlling 
the admission of steam to the second and later stages 
differ from those in the first group in that they partake 
more of the nature of slide-valves and may be operated 
either by hand or automatically; in fact, they require but 
very little regulation, as the governing is always done by 







320 QUESTIONS AND ANSWERS 


the live-steam admission-valves. As previously stated, 
the steam first strikes the moving blades in the first stage 
of a two-stage machine at a pressure of about 15 pounds 



Fig. 196. Governor for 5,000 K. W. Turbine. 


above atmospheric pressure, but with great velocity. 
From this wheel it passes to the set of stationary blades 
between it and the next lower wheel. These stationary 
blades change the direction of flow of the steam and cause 













STEAM TURBINE-FUNDAMENTAL PRINCIPLES 321 




it to impinge against the buckets of the second wheel at 
ihe proper angle. 

Ques. 734.—How is speed-regulation accomplished in 
:he Curtis steam turbine? 

Ans.—The governing of speed is accomplished in the 
irst set of nozzles, and the control of the admission-valves 
lere is effected by means of a centrifugal governor 
ittached to the top end of the shaft. This governor, by 



Fig. 197. Electrically Operated Valve. 


i very slight movement, imparts motion to levers, which 
n turn work the valve mechanism. The admission of 
.team to the nozzles is controlled by piston-valves which 
ire actuated by steam from small pilot-valves which are 
n turn under the control of the governor. Speed-regu- 
ation is effected by varying the number of nozzles in 
low, that is, for light loads fewer nozzles are open and a 
smaller volume of steam is admitted to the turbine wheel, 
aut the steam that is admitted impinges against the mov- 









322 QUESTIONS AND ANSWERS 

ing blades with the same velocity always, nz matter whether 
the volume be large or small. With a full load and all 
the nozzle sections in flow, the steam passes to the wheel 
in a broad belt and steady flow. 


Fig. 198. 5,000 Kilowatt Generating Units. 

Comparison of space occupied and size of foundations. Modern Engine 
Type Unit and a Westinghouse*Parsons Turbine Type Unit of similar rating 
And overload capacity. 

Ques. 735.—What great advantage does the steam- ■ 
lurbine as a prime mover for an electric generator 
possess over the reciprocating engine? 

An*.—The advantage of a high speed of revolution 





































































STEAM TURBINE— FUNDAMENTAL PRINCIPLES 323 

whereby there can be a great reduction in the size, 
weight, and cost of the direct-driven generator. 

Ques. 736.—Give approximately the over-all dimen¬ 
sions of a Westinghouse-Parsons turbo-generator unit of 
5,500-kilowatt, 11,000 volt capacity, of the revolving field 
type, speed 750 revolutions per minute, vacuum to be 
27/4 inches. 

Ans.—Length 47 feet, width 13 feet, and height 
14 feet to top of gallery-ring. 



Fig. 199. General View of a 400 K. W. Turbine Generator Unit. 

Ques. 737.—What amount of floor-space would a 
reciprocating engine and direct-connected generator of 
equal capacity with the above occupy? 

Ans.—The generator would be 42 feet in extreme 
diameter, its weight would be 445 tons (speed to be 75 
revolutions per minute) and it, together with the four- 
cylinder piston engine, would fill a space 40 feet wide by 
60 feet long, and tower 45 feet in height. 

Ques. 738.—Describe in general terms the construe- 



324 


QUESTIONS AND ANSWERS 


tion and principles of operation of the Westinghouse- 
Parsons steam-turbine. 

Ans.—The Westinghouse-Parsons steam-turbine is 
fundamentally based upon the invention of Mr. Charles 
A. Parsons, who, while experimenting with a reaction 
turbine constructed along the Il“?s of Hero’s engine, con¬ 
ceived the idea of combining the two principles, reaction 



Fig. 200. Shows a 600 H. P. machine with the upper half of the cylinder, or 
stator as it is termed, thrown back for inspection. 

and impulse, and also of causing the steam to flow in a 
•general direction parallel with the shaft of the turbine. 
This principle of parallel flow is common to all four types 
of turbines, but is perhaps more prominent in the 
Westinghouse-Parsons and less so in the De Laval. The 
cylinder, or stator, as it is termed, is divided longitudinally 
into an upper and a lower half flanged and bolted together. 
There are three sections or drums, gradually increasing 




















STEAM TURBINE-FUNDAMENTAL PRINCIPLES 325 

in diameter from the inlet to the third and last group of 
blades. This arrangement may be likened in some 
measure to the triple-compound reciprocating engine. 

Ques. 739.—Describe the arrangement of the blades 
or buckets in the Westinghouse-Parsons steam-turbine. 

Ans.—There are two kinds of blades, viz., stationary 
blades and moving blades, but they are similar in shape, 
being of the same curvature. These blades are made of 
hard drawn material, and are set into their places and 
secured by a caulking process. The stationary blades 
project from the inside surface of the cylinder, while 
similar rows of moving blades project from the surface 
of the rotor, or revolving drum. When the upper half 
of the cylinder is in position each row of stationary blades 
fits in between two corresponding rows of moving blades. 

Ques. 740.—Are these blades all of the same length? 

Ans.—They are not. The length varies from /4 inch 
for the shortest to 7 inches for the longest, according to 
their location. The shortest blades are placed at the 
steam end of each section and the longest blades are 
placed at the opposite end. 

Ques. 741.—What is the clearance between the blades 
as they stand in the rows? 

Ans.—The clearance between the blades as they stand 
in the rows is ]/% inch for the smallest size blades and Yi 

inch for the larger ones, gradually increasing from the 
inlet to the exhaust. In the 5,000 kilowatt machine the 
clearance at the exhaust end between the rows of blades 
is 1 inch. 

Ques. 742.—What is the general direction taken by 






326 


QUESTIONS AND ANSWERS 


the steam in its passage through the Westinghouse-Par- 
. sons turbine? 

Ans.—The steam entering at the smaller end of the 
cylinder presses first against the shortest blades and then 
passes on through in the form of spiral or screw line about 
the rotor, continually pressing against new and gradually 
lengthening blades, thus doing work by reason of its 
velocity. 


2 


STATIONARY BLADES 

i> J> J) iip TTJ 


~ JIU n> 1U 


MOVING BLADES 


STATIONARY BLADES; 




MOVING BLADES 


Fig. 201. Sectional View op Four Rows op Blades, of a Westinghouse* 

Parsons Turbine. 

Ques. 743.—As steam presses equally in all directions, 
is there not a very heavy end-thrust exerted by the rotor? 


Ans.—There is not. The pressure in either direc¬ 
tion is perfectly balanced by means of balancing pistons 
placed on the steam end of the rotor. The diameters of 
these pistons correspond to the diameters of the different 1 

I 

drums or sections.* 

Ques. 744.—About what is the velocity of the steam 
in the Parsons turbine? 


*The theory and action of these balancing pistons is fully 
and completely described in Swingle’s “Twentieth Century Hand 
Book for Engineers and Electricians.” 











STEAM TURBINE-FUNDAMENTAL PRINCIPLES 327 


Ans.—The highest velocity does not exceed 600 feet a 
i second. 

Ques. 745.—About what amount of pressure is 
1 exerted upon each blade by the steam? 

Ans.—The steam-thrust on each blade is said to be 
equal to about 1 ounce avoirdupois. 

Ques. 746.—With such a very light pressure upon 



■ 

Fig. 202. Sectional View oe a Westinchouse-Parsons Turbine, Showing 
Arrangement of Balancing Pistons P. P. P. 

each blade, why is it that this turbine is capable of devel¬ 
oping power? 

Ans.—Because of the large number of blades; as, for 
instance, taking a 400 kilowatt machine, there are 16,095 
moving blades and 14,978 stationary blades, a total of 
31,073. 

Ques. 747.—How are the clearances preserved? 

Ans.—A rigid shaft and thrust or adjustment bearing 
accurately preserves the clearances. 











































328 


QUESTIONS AND ANSWERS 


Ques. 748.—Describe the construction and action of 
the bearings. 

Ans.—The bearings are constructed along lines differ¬ 
ing from those of the ordinary reciprocating engine. The 
bearing proper is a gun-metal sleeve that is prevented 
from turning by a loose-fitting dowell. Outside of this 
sleeve are three concentric tubes having a small clearance 
between them. This clearance is kept constantly filled 
with oil supplied under light pressure, which permits a 
vibration of the inner shell or sleeve and at the same time 
tends to restrain or cushion it. This arrangement allows 
the shaft to revolve about its axis of gravity instead of 
the geometrical axis, as would be the case if the bearing 
were of the ordinary construction. The journal is thus 
to a certain degree a floating journal, free to run slightly 
eccentric according as the shaft may happen to be out of 
balance. 

Ques. 749.—How is the power of the Westinghouse- 
Parsons turbine transmitted to the dynamo, or other 
machine to be run? 

Ans.—A flexible coupling is provided, by means of 
which the power of the turbine is transmitted to the 
dynamo other machine it is intended to run. The oil 
from all the bearings drains back into a reservoir, and 
from there it is forced up into a chamber, where is forms 
a static head, which giv^s a constant pressure of oil on 
all the bearings. 

Ques. 750.—How is the speed governed? 

Ans.—The speed of the Westinghouse-Parsons 
turbine is regulated by a flv-ball governer constructed in 












STEAM TURBINE—FUNDAMENTAL PRINCIPLES 329 


such manner that a very slight movement of the balls 
serves to produce the required change in the supply of 
steam. The ball levers swing on knife edges instead of 
pins. The governor works both ways, that is to say, 
when the levers are oscillating about their mid position a 
head of steam corresponding to full load is being admitted 
to the turbine, and a movement from this point, either up 
or down, tends to increase or to decrease the supply of 
steam. 



I 

Ques. 751.—What can be said of the efficiency of the 
Westinghouse-Parsons steam-turbine? 

Ans.—Under test a 400 kilowatt Westinghouse-Par- 
J sons steam-turbine, using steam at 150 pounds initial 
pressure and superheated about 180 degrees, consumed 
11.17 pounds of steam per brake horse-power hour at full 
load. The speed was 3,550 revolutions per minute and 
the vacuum was 28 inches. With dry saturated steam 







































































330 


QUESTIONS AND ANSWERS 


the consumption was 13.5 pounds per brake horse-power 
hour at full load, and 15.5 pounds at one-half load. A 
1,000 kilowatt machine, using steam of 150 pounds pres- j 
sure and superheated 140 degrees, exhausting into a , 
.vacuum of 28 inches, showed the very remarkable 
‘.economy of 12.66 pounds of steam per electrical horse¬ 
power per hour. A 1,500 kilowatt Westinghouse-Par- 
son turbine, using dry saturated steam of 150 pounds 
pressure with 27 inches vacuum, consumed 14.8 pounds j 
steam per electrical horse-power hour at full load, and , 
17.2 pounds at one-half load. 

Ques. 752.—What efficiency does the Curtis turbine 
show in the use of steam? 

Ans.—A 600 kilowatt Curtis turbine operating at 
1,500 revolutions per minute, with steam at 140 pounds 
gaugt-pressure and 28.5 inches vacuum, showed a steam- 
consumption as follows, steam superheated 150 degrees: 
At full load, 12.5 pounds per electrical horse-power per 
hour; at half load, 13.25 pounds per electrical horse-power 
per hour; at one-sixth load, 16.2 pounds per electrical 
horse-power per hour, and at one-third overload, 12.4 
pounds per electrical horse-power per hour. <j 

| Ques. 753.—Describe in brief terms the Hamilton- 
Holzwarth steam-turbine. 

Ans.—The Hamilton-Holzwarth steam-turbine is 
based upon and has been developed from the designs of 
Prof. Rateau, and is being manufactured in this country 
by the Hooven-Owens-Rentschler Company, of Hamilton, 
Ohio. It is horizontal and placed upon a rigid bed-plate 
of the box pattern. All steam, oil and water-pipes are 






STEAM TURBINE-FUNDAMENTAL PRINCIPLES 331 

' within and beneath this bed-plate, as are also the steam- 
i inlet-valve and the regulating and by-pass valves. The 
smaller sizes of this turbine are built in a single casing or 
i cylinder, but for units of 750 kilowatts and larger the 
i revolving element is divided into two parts, high and low 
pressure. This turbine resembles the Westinghouse-Par- 
■ sons turbine in some respects, prominent of which is that 
it is a full-stroke turbine, that is, that the steam flows 
i through it in one continuous belt or veil in screw line, 

I the general direction being parallel with the shaft. But, 
unlike the Parsons type, the steam in the Hamilton-Holz- 
; warth turbine is made to do its work only by impulse, 
and not by impulse and reaction combined. It might 
thus be termed an action turbine. 

Ques. 754.—Describe the interior construction of this 
turbine. 

Ans.—The interior of the cylinder is divided into a 
series of stages by stationary disks which are set in 
grooves in the cylinder and are bored in the center to 
allow the shaft, or rather the hubs of the running wheels 
that are keyed to the shaft, to revolve in this bore. 
There are no balancing pistons in this machine, the axial 
thrust of the shaft being taken up by a thrust ball-bear¬ 
ing. Between each two stationary disks there is located 
a running wheel, and the clearam 



vanes and the stationary vanes 


consistent with safe practice. 

Ques. 755.—Describe the construction of the running 
vanes and the action of the steam upon them. 

Ans.—The running vanes conform in section somewhat 





332 


QUESTIONS AND ANSWERS 





to the Parsons type, but the action of the steam upon 
them and also within the stationary vanes is different. The 
expansion of the steam and 
consequent development of 
velocity takes place entirely 
within the stationary vanes, 
which also change the direc¬ 
tion of flow of.the steam and 
distribute it in the proper 
manner to the vanes of the 
running wheeis, which, ac¬ 
cording to the claims of the 
makers, the steam enters 
and leaves at the same pres¬ 
sure, thus allowing the 
wheel to revolve in a uni¬ 
form pressure. 

Ques. 756.—What pro¬ 
vision is made in the Hamil- 

ton-Holzwarth turbine for 

! 

maintaining the velocity of 
the steam as it expands? 

Ans.—The first station¬ 
ary disk of the low-pressure 
turbine has guide-vanes all 
around its circumference, 
so that the steam enters the 
turbine in a full cylindrical belt,interrupted only by the 
guide-vanes. To provide for the increasing volume as 
the steam expands in its course through the turbine, the 


Fig. 204. General View of a Hamilton-Holzwarth Steam-Turbine. 











STEAM TURBINE-—FUNDAMENTAL PRINCIPLES 333 


reas of the passages through the distributers and running 
anes must be progressively enlarged. The gradual in- 
rease in the dimensions of the stationary vanes permits 
he steam to expand within them, thus tending to maintain 
:s velocity, while at the same time the vanes guide the 
team under such a small angle that the force with which 
: impinges against the vanes of the next running wheel 
5 as effective as possible. The curvature of the vanes is 
uch that the steam while passing through them will in- 
jrease its velocity in a ratio corresponding to its oper- 
tion. 

Ques. 757.—Describe the method of regulating the 
peed of this turbine. 

Ans.—The governor is of the spring and weight type, 
.dapted to high speed, and is designed especially for 
urbine governing. It is directly driven by the turbine- 
haft, revolving with the same angular velocity. Its action 
s as follows! Two disks keyed to the shaft, drive, by 
neans of rollers, two weights sliding along a cross-bar 
placed at right angles through the shaft and compressing 
wo springs against two nuts on the cross-bar. Every 
jnovement of the weights, caused by increasing or decreas- 
ng the angular velocity of the turbine-shaft, is trans- 
nitted by means of levers to a sleeve which actuates the 
•egulating mechanism. These levers are balanced so that 
10 back pressure is exerted upon the weights. The whole 
governor is closed in by the disks, one on each side, and a 
steel ring secured by concentric recesses to the disks. In 
order to decrease the friction within the governor and 
regulating mechanism, thrust ball-bearings and friction- 
1 less roller-bearings are used. 






334 


QUESTIONS AND ANSWERS 


Ques. 758.—Describe the action of the steam within 
th3 Hamilton-Holzwarth steam-turbine. 

Ans.—After leaving the steam-separator that is 
located beneath the bed-plate, the steam passes through 
the inlet or throttle-valve, the stem of which extends up 
through the floor near the high-pressure casing and is 
protected by a floor-stand and equipped with a hand 
wheel. The steam now passes through the regulating 
valve, which will be described later on. From this valve 
it is led through a curved pipe to the front head of the 
high-pressure casing or cylinder. In this head is a ring 
channel into which the steam enters, and from whence it 
flows through the first set of stationary vanes. 

Ques. 759.—Describe the action of the steam as it 
passes through the first set of stationary vanes. 

Ans.—In these vanes the first stage of expansion 
occurs, the velocity of the flow is accelerated, and the 
direction of flow is changed by the curve of the vanes in 
such manner that the steam impinges against the vanes 
of the first running wheel at the proper angle and in a full 
cylindrical belt, imparting by impulse a portion of its 
energy to the wheel. 

Ques. 760.—What takes place in the course of the 
steam after leaving the first running wheel? 

Ans.—Passing through the vanes of this wheel, the 
steam immediately enters the vanes of the second station¬ 
ary disk, which are larger in area than those of the first, 
and here occurs the second stage of expansion, another 
acceleration of velocity, and also the proper change in 
direction, and the steam leaves this distributer and 











STEAM TURBINE-FUNDAMENTAL PRINCIPLES 335 

impinges against the vanes of the second running wheel. 
This cycle is repeated throughout the several stages of 
the turbine, a certain percentage of the heat energy in the 
steam being imparted by impulse to each wheel and thence 
to the turbine-shaft. From the last running wheel the 
steam is led through receiver pipes to the front head of 
the low-pressure cylinder, or, if there is but one cylinder, 
directly to the condenser or the atmosphere. 

Ques. 761.—Describe the construction and location 
of the regulating valve. 

Ans.—The regulating valve is located beneath the 
bed-plate. One side of it is connected by a curved pipe 
with the front head of the high-pressure cylinder and the 
other side is connected with the inlet-valve. The regulat¬ 
ing valve is of the double-seated poppet-valve type. 
Valves and valve-seats are made of tough cast steel, to 
avoid corrosion as much as possible, and the valve-body 
is made of cast iron. 

Ques. 762.—Describe the by-pass regulating valve. 

Ans.—This valve is also a double-seated poppet-valve 
and is located immediately below the regulating valve and 
forming a part of it. Thus the use of a second stuffing 
pox for the stem of this valve is avoided. The function 
bf this valve is to control the volume of the live-steam 
supply that flows directly to the by-pass nozzles in the 
front head of the low-pressure casing. 

Ques, 763.—How is the main regulating valve 
operated? 

Ans.—The main regulating valve is not actuated 
iirectly by the governor, but by means of the regulating 










336 


QUESTIONS AND ANSWERS 


Ques. 764.—Describe the construction and operation 
of the regulating mechanism of the Hamilton-Holzwarth 
steam-turbines. 

Ans.—The construction and operation of this regulat¬ 
ing mechanism is as follows: The stem of the regulating 
valve is driven by means of bevel gears by a shaft that is 
supported in frictionless roller-bearings. On this shaft 
there is a friction wheel that the governor can slide across 
the face of a continuously revolving friction disk by 
means of its sleeve and bell-crank lever. This revolving 
disk is keyed to a solid shaft which is driven by a coupling 
from a hollow shaft. This hollow shaft is driven by the 
turbine-shaft through the medium of a worm gear. The 
solid shaft, with the continuously revolving friction disk, 
can be slightly shifted by the governor sleeve so that the 
two friction disks come into contact when the sleeve 
moves, that is, when the angular velocity changes. If 
this change is relatively great, the sleeve will draw the 
periodically revolving friction disk far from the center of 
the always revolving one, and this disk will quickly drive 
the stem of the regulating valve and the flow of steam will 
thus be regulated. As soon as the angular velocity falls 
below a certain percentage of the normal speed, the 
driving friction disk is drawn back by the governor, the 
regulating valve remains open and the whole regulating 
mechanism rests or stops, although the shaft is still 
running. 

Ques. 765.—Under what conditions will this governor 
shut down the turbine? 

Ans.—Should the angular velocity of the shaft reach 



STEAM TURBINE-FUNDAMENTAL PRINCIPLES 33? 

i point 2.5 per cent higher than normal, the governor will 
hut down the turbine. If an accident should happen to 
he governor, due to imperfect material or breaking or 
weakening of the springs, the result would be a shut- 
own of the turbine. 

Ques. 766.—How may the speed of this turbine be 
hanged, while running, if necessary? 

Ans.—In order to change the speed of the turbine 
/hile running, which might be necessar}' in order to run 
he machine parallel with another prime mover, a spring 
ialance is provided, attached to the bell-crank lever of 
he regulating mechanism. The hand-wheel of this spring 
ialance is outside of the pedestal for regulating mechanism 
nd near the floor-stand and hand-wheel. With this 
pring balance the speed of the turbine may be changed 
per cent either way from normal. 

Ques. 767.—What is the best method of disposing of 
the exhaust steam of steam-turbines? 

Ans.—As in the case of the reciprocating engine, the 
ighest efficiency in the operation of the steam-turbine is 
btained by allowing the exhaust steam to pass into a 
ondenser, and experience has demonstrated that it is 
possible to maintain a higher vacuum in the condenser of 
. turbine than in that of a reciprocating engine. This 
s due, no doubt, to the fact that in the turbine the steam 
s expanded down to a much lower pressure than is pos- 
ible with the reciprocating engine. 

Ques. 768.—What type of condensing apparatus is 
►est adapted to steam-turbines? 

Ans.—The condensing apparatus used in connection 




338 QUESTIONS AND ANSWERS 

with steam-turbines may consist of any one of the 
modern improved systems, and as no cylinder-oil is used 
within the cylinder of the turbine, the water of condensa¬ 
tion may be returned to the boilers as feed-water. If the 
condensing water is foul or contaii-J matter that would 
be injurious to the boilers, a surface condenser should be 
used. If the water of condensation is not to be used in 
the boilers, the jet system may be employed. 

Ques. 769.—What percentage of gain may be effected 
by allowing the exhaust steam from the turbine to pass 
into a good condenser? 

Ans.—As an instance of the great gain in economy 
effected by the use of the condenser in connection with 
the steam-turbine, a 750 kilowatt Westinghouse-Parsons 
turbine, using steam of 150 pounds pressure, not super¬ 
heated and exhausting into a vacuum of 28 inches, showed 
a steam consumption of 13.77 pounds per brake horse¬ 
power per hour, while the same machine operating non¬ 
condensing consumed 28.26 pounds of steam per brake 
horse-power hour. Practically the same percentage in 
economy effected by condensing the exhaust applies to 
the other types of_steam-turbines. 

Ques. 770.—About what is the additional cost of 
operating a complete condensing outfit in connection 
with a steam-turbine plant? 

Ans.—With reference to the relative cost of operating 
the several auxiliaries necessary to a complete condensing 
outfit, the highest authorities on the subject place the 
power consumption of these auxiliaries at from 2 to 7 per 
cent of the total turbine output of power. A portion of 




STEAM TURBINE-FUNDAMENTAL PRINCIPLES 339 

! this is regained by the use of an open heater for the feed- 
! water, into which the exhaust steam from the auxiliaries 
may pass, thus heating the feed-water and returning a 
part of the heat to the boilers. 

Ques. 771.—What precautions must be observed in 
the operation of a condensing outfit in order to obtain the 
highest efficiency? 

Ans.—A prime requisite to the maintenance of high 
vacuum, with the resultant economy in the operation of 
the condensing apparatus, is that all entrained air must 
be excluded from the condenser. There are various ways 
in which it is possible for air to find its way into the con¬ 
densing system. For instance, there may be an improp¬ 
erly packed gland, or there may be slight leaks in the 
piping, or the air may be introduced with the condensing 
water. This air should be removed before it reaches the 
condenser, and it may be accomplished by means of the 
“dry” air-pump. 

Ques. 772.—Describe some of the leading character¬ 
istics of the dry air-pump. 

Ans.—This dry air-pump is different from the 
ordinary air-pump that is used in connection with most 
j condensing systems. The dry air-pump handles no 
water, the cylinder being lubricated with oil in the same 
* manner as the steam-cylinder. The clearances also are 
made as small as possible. These pumps are built either 

I in one or two stages. 

Ques. 773.—What particular features would be 
required in the design of a compound or stage-expansion 
reciprocating engine, in order to develop a high vacuum, 
for instance as high as 28.5 inches? 











340 QUESTIONS AND ANSWERS 

Ans.—In comparing the efficiency of the reciprocating 
engine and the steam-turbine it is not to be inferred that 
reciprocating engines would not give better results at 
high vacuum than they do at the usual rate of 25 to 2G 
inches, but to reach and maintain the higher vacuum of 
28 to 28.5 inches with the reciprocating engine would 
necessitate much larger sizes of the low-pressure cylinder, 
as also the valves and exhaust pipes, in order to handle 
the greatly increased volume of steam at the low-pressure 
demanded by high vacuum. 

Ques. 774.—What advantage has the turbine over the 
reciprocating engine, in the disposal of its exhaust 
steam? 

Ans.—The steam-turbine expands its working steam 
to within 1 inch of the vacuum existing in the condenser, 
that is, if there is a vacuum of 28 inches in the condenser 
there will be 27 inches of vacuum in the exhaust end of 
the turbine cylinder. On the other hand, there is usually 
a difference of 4 or 5 inches (2 to 2.5 pounds) between 
the mean back pressure in the cylinder of a reciprocating 
condensing engine and the absolute back pressure in the 
condenser. 

Ques. 775.—Mention the two principal sources of 
economy that the steam-turbine possesses in a high 
degree. 

Ans.—Two of the main sources of economy that the 
steam-turbine possesses in a much higher degree than 
does the reciprocating engine are: First, its adaptability 
for using superheated steam, and second, the possibility 
of maintaining a higher degree of vacuum. 



Fig. 205. The Aleis Chaemers Steam Turbine. 























342 


QUESTIONS AND ANSWERS 


Ques. 776.—What can be said of the steam turbine, 
regarding friction of rubbing parts, such as reciprocating 
pistons, cross-heads, etc? 

Ans.—There are no rubbing surfaces in the turbine 
except the bearings of the rotor. 

Ques. 777.—Of what type is the Allis Chalmers steam- 
turbine? 

Ans.—It is of the reaction, or Parsons type, with a 
number of modifications in details of construction. 

Ques. 778.—Give an elementary description of the 
“Parsons” steam-turbine. 

Ans.—It consists essentially of a fixed casing, or 
cylinder, usually arranged in three stages of different 
diameters, that of the smallest diameter being at the high- 
pressure, or admission end, and that of the largest diam¬ 
eter at the low-pressure or exhaust end of the casing. 

Inside of this casing is a revolving drum, or rotor, the 
ends of which are extended in the form of a shaft, and 
carried in two bearings, just outside each end of the cyl¬ 
inder. 

Ques. 779.—What causes the drum to revolve within 
the cylinder? 

Ans.—The drum is fitted with a large number of small 
curved blades, or paddles arranged in straight rows 
around its circumference. The blades in each stage, or 
step, are also arranged in groups of increasing Jength, 
those at the beginning of each larger stage being shorter 
than those at the end of the preceding stage, the change 
being made in such a manner that the correct relation of 
blade length to drum diameter is secured. These rows of 


STEAM TURBINE-FUNDAMENTAL PRINCIPLES 343 

• 

revolving blades fit in and run between corresponding 
rows of stationary blades that project from the walls of 
the cylinder. These stationary blades have the same cur¬ 
vature as the revolving blades, but are set so that the 
curves incline in the opposite direction to those of the 
revolving blades. The steam entering the cylinder at the 
smallest or first stage, is deflected in its course by the 
first row of stationary blades, and immediately impinges 
with a pressure but slightly reduced from boiler pressure, 
against the first row of revolving blades. It then passes 



Main bearings, A and B. Thrust bearing, R, Steam pipe, C. Main throttle 
valve, D. which is balanced, and operated by the governor. Steam enters the 
cylinder through passage E, passes to the left through the alternate rows of 
stationary and revolving blades, leaving the cylinder at F and passes into the 
condenser, or atmosphere through passage G. H, J and K are the three steps or 
stages of the machine. L, M and N are the three balance pistons. O, P and 
Q are the equalizing passages, connecting the balance pistons with the corres¬ 
ponding stages. 


to the next row of stationary blades, which again deflect 
its course so as to cause it to strike the next row of mov¬ 
ing blades at the proper angle. Thus the continual 
pressure and reaction of the steam against the curved 
surfaces of the moving blades causes the drum, or rotor 
to revolve. 




































































































Fig. 207. Spindle or Rotor, Allis Chalmers Steam Turbine. 
The rings which carry the blades are pressed on. 





















STEAM TURBINE-FUNDAMENTAL PRINCIPLES 345 


Ques. 780.—Does not the action of the steam against 
the revolving blades tend to produce a strong end thrust? 

Ans.—It does—but this thrust is neutralized by three 
“balance-pistons’' so called, which are fitted upon the 
revolving drum at the high-pressure end of the cylinder. 
The diameter of each “piston” corresponds with the 
diameter of that stage of the cylinder with which it is 
connected by an equalizing passage which permits the 
steam to act upon it, and thus balance the thrust. 





Fig. 208 showing arrangement of blading and course of the steam in Parsont 
Bteam turbine. 


Ques. 781.—Do the revolving blades come in contact 
with the stationary parts? 

Ans.—They do not. The high speeds which are nec¬ 
essary in the steam turbine prohibit any continuous con- 



















346 


QUESTIONS AND ANSWERS 


tact between moving and stationary parts, except in the 
lubricated bearings. 

Ques. 782.—How much clearance is allowed between ' 
the moving and stationary parts in the ‘‘Parsons” steam- ! 
turbine? j 

^ Ans.—The tips of the revolving blades just clear the 
walls of the cylinder, and the tips of the stationary blades 
just clear the surface of the rotor. 



Fig. 209. 


S« ^ St «°h n e VS S,r N 1 X^r r F e , 8 e '& yet O h a a n V ( i n d ' h i 


Ques. <83. How are the clearances between the 
edges of the revolving and stationary blades preserved? 


Ans. The position of the drum, as regards end play, 
is definitely fixed by means of a small “thrust bearing” 
provided inside the housing of the main bearing. 

This so-called thrust bearing can be adjusted to locate. 

















































































STEAM TURBINE-FUNDAMENTAL PRINCIPLES 347 

e and hold the revolving spindle or rotor in such position as 
will allow sufficient clearance between the moving and 
3 stationary blades, and yet reduce the leakage of steam to 
■ a minimum. 

Ques. 784.—Is there not danger of out leakage of 
e steam, and in leakage of air, where the shaft passes out 
$ of the high and low-pressure ends of the cylinder? 

Ans.—There is; but this is provided for by glands 
that are made practically frictionless by water packing, 
without metallic contact. 

Ques. 785.—How is the power of the “Parsons” type 
of steam-turbine transmitted to the electric generator, or 
other machine to be run? 

Ans.—The shaft is extended at the low-pressure end, 
and coupled to the shaft of the generator by means of a 
flexible coupling. 

Ques. 786.—What provision is made in this type of 
]steam-turbine for speed regulation? 

Ans.—The speed of the “Parsons” turbine is regu¬ 
lated by a very sensitive governor driven from the turbine 
shaft by means of cut gears working in an oil bath. The 
governor operates a balanced throttle-valve, and may be 
adjusted for speed while the turbine is in motion if 
necessary for the synchronizing of alternators, and divid-| 
ing the load. 

Ques. 787.—Suppose there should be an accidental 
derangement of the governing mechanism, what provision 
is made for preventing dangerous over speed? 

Ans.—A separate safety governor is provided, driven 
directly by the turbine shaft, without the intervention of 





348 


QUESTIONS AND ANSWERS 


gearing, and so adjusted that if the speed of the turbirn 
should reach a predetermined point above that for which 
the main governor is set, the safe„u governor will com< 
into action, and trip a valve, thus shutting off the steam 
and stopping the turbine. 

Ques. 788.—Is the arrangement of “balance-pistons’ 
described in answer to question 780 carried out in al 
sizes of steam-turbines of the “Parsons” type? 

Ans.—No. In the larger sizes of the Allis Chalmers 
steam-turbine, the largest one of the three pistons at the 
high-pressure end is replaced by a smaller balance-piston 
located at the low-pressure end of the turbine, and work- 
ing inside a supplementary cylinder. 

This piston presents the same effective area for the 
steam to act upon, as did the larger piston, because the 
working area of the latter in its original location con¬ 
sisted only of the annular area included between its 
periphery, and the periphery of the next smaller piston. 

Ques. 789.—How is the pressure of the steam brought 
to bear upon this equalizing piston in its new position? 

Ans.—By means of passages through the body of the 
rotor, connecting the third stage of the cylinder with 
the supplementary cylinder in which the piston revolves. 

Ques. 790. —How are the blades or paddles fitted to, 
and held in the rotor, and cylinder of the Allis Chalmers 
steam-turbine? 

Ans. Each blade is individually formed by special 
machine tools, so that its root or foot is of an angular 
dove-tail shape, and at its tip there is a projection. 

Foundation rings are provided for each row of blades. 









Fig. 210. 

Half ring of blades inserted in the foundation ring before being placed upon the rotor, showing substantial construction. 








35U 


QUESTIONS AND ANSWERS 


These rings have slots of dove-tail shape cut into ther 
to receive the roots of the blades. These slots are accu 
rately spaced, and inclined so as to give the require* 
pitch and angle to the blades. The foundation ring 
themselves are dove-tail in cross section, and are inserted 
in dove-tail grooves cut in the turbine cylinder, and rotoi 
respectively. These rings are firmly held in place by ke} 
pieces that are driven into place, and upset into undercut 
grooves, thus locking the whole structure firmly together. 

Ques. 791.—How are the tips or outer ends of the 
blades protected? 

Ans.—By a shroud ring for each row, in which holes 
are punched to receive the projections on the tips of the 
blades. 

These holes are spaced by special machinery to match 
the slots in the foundation ring. 

Ques. 792.—Describe the construction of the shroud 
rings. 

Ans.—They are channel shaped in cross section, and 
are made thin, so that in case of accidental contact with 
an opposing surface no dangerous heating will occur, 
neither will the rubbing be so liable to rip out the blades, 
as it is when they are unprotected by a shroud ring. 

Ques. 793.—Mention another advantage in connection 
with the use of a shroud ring. 

Ans.—The blades in each row are stiffened, and held| 
together as a unit by its use, thus permitting smaller 
clearances, and reducing the leakage loss to a minimum. 
The channel shape of the shroud ring also forms an 
effective baffle to the steam leakage. 










Fig. 

turbine. 


211 illustrates blades as fitted in the rotor of Allis Chalmers steam 
The shroud ring protecting the tips of the blades is also shown. 




















352 


QUESTIONS AND ANSWERS 



Ques. 794.—What type of bearings are the Allis 
Chalmers steam-turbines fitted with? 

Ans.—Self-adjusting ball and socket bearings espe¬ 
cially designed for high speed, shims being provided for 
proper alignment. 


Fig. 212. 

Fig. 212 shows a number of rows of stationary blades fitted in the cylinder of 
an Allis Ch almers steam turbine. 

In the smaller sizes the bearing shells are made of 
special bronze, and in the larger sizes white metal is used 
for bearing surface. 



















STEAM TURBINE —FUNDAMENTAL PRINCIPLES 353 


S 

Ques. 795.—How are these bearings lubricated? 

Ans.—The oil is supplied freely to the middle of each 
. bearing, and allowed to flow out at the ends, where it is 
caught, passed through a cooler, and pumped back to the 
bearings, to be used again and again. 

Ques. 796.—Does the fact that the oil is supplied 
to the bearings in large quantities necessarily imply a 
j| heavy expenditure for oil? 

Ans.—It does not; for the reason that the bearings 
practically float on oil films, thus preventing that “wear¬ 
ing out” of the oil which occurs when it is supplied in 
diminutive doses. 

Ques. 797.—Can superheated steam be used to advan¬ 
tage in steam-turbines? 

Ans.—It can; in fact the steam-turbine has solved the 
problem of superheated steam, owing to the absence of 
all rubbing parts exposed to the steam. This permits the 
use of steam of high temperature thus making it possible 
to realize the advantages of economical operation. 

Ques. 798.—Is there not danger of distortion of the 

turbine cylinder being caused by the very high tempera- 

# 

tures to which it is exposed by the use of superheated 
. steam? 

Ans.—There have been numerous instances in the past 
of unequal expansion of the top, and bottom of the cylin- 
1 der thereby causing the rotating blades to come in 

I contact with the cylinder walls, and be ripped out, but this 

II 

difficulty has in a great measure been overcome by certain 
' designers of steam-turbines, who have made a special 
study of the laws of expansion and contraction of metals, 

















354 


QUESTIONS AND ANSWERS 


and have thus been enabled to make such a distribution 
of the metal, as to cause an equal expansion of all parts 
of the cylinder. 

Ques. 799.—What effect does the accidental carrying' 
over of water with the steam, have upon the steam-tur¬ 
bine? 

Ans.—The sudden presence of a quantity of water 
with the steam, caused by foaming or priming of the boil¬ 
ers, would cause no more serious results than the slowing 
down of the turbine during the time necessary to permit 
the water to be discharged from the exhaust end. 

Ques. 800.—What may be said in general of the 
steam-turbine? 

Ans.—It has passed through the experimental stage, 
and has come to the front, as an efficient power pro¬ 
ducer, having a bright future before it. 


DE LAVAL STEAM TURBINE. 

CLASS C. 

Ques. 801.—In what respect does the Class C De 
Laval Turbine differ mainly from the regulation type of 
De Laval Turbine referred to on pages 304 to 314? 

Ans.—In the construction of the buckets, and guide 
vanes; also in the accessibility of the parts. 

Ques. 802.—Describe the construction of the buckets 
in this type of steam Turbine. 

Ans.—The buckets are made of nickel-bronze and 
are secured to the rim of the wheel by bulb shanks. 
They may also be replaced individually without disturb¬ 
ing other buckets. 



STEAM TURBINE-FUNDAMENTAL PRINCIPLES 355 

Ques. 803.—Describe the construction of the guide 
vanes in the Class C Turbine. 

Ans.—The guide vanes are of nickel-bronze, and are 
attached to steel retaining rings in the same manner as 
are the rotating buckets. 

Ques. 804.—What can be said in favor of this meth¬ 
od of attaching guide vanes, and buckets? 

Ans.—It is superior to the common method of cast¬ 
ing these important parts of the turbine in with a por¬ 
tion of the casing, or the rim of the wheel. 

Ques. 805.—Give a reason for this. 

Ans.—If guide vanes, or buckets that are cast in, 
should become corroded, and need replacing, it is neces¬ 
sary to replace a portion of the casing, or the wheel rim, 
in order to bring the turbine back to its original effi¬ 
ciency. 

Ques. 806.—What amount of work is necessary in 
order to replace one, or more of these parts in the Class 
C De Laval Steam Turbine? 

Ans.—See answer to question 802. 

Ques. 807.—How are changes in boiler pressure, or 
in vacuum, provided for in the Class C Turbine? 

Ans.—By simply replacing the nozzles by others de¬ 
signed for the new ratio of expansion. 

Ques. 808.—Is this possible in turbines in which the 
nozzles are a permanent part of the main turbine struc¬ 
ture ? 

Ans.—It is not. 

Ques. 809.—How is the speed of the Class C De 
Laval Turbine controlled? 







356 


QUESTIONS AND ANSWERS 


Ans.—Two governors are provided, one of which is 
called the emergency governor. 

Ques. 810.—In what way may a turbine governor be 
rendered useless, and still retain all its parts unbroken? 

Ans.—By the valves becoming clogged with scale, 
waste or other foreign matter. 

Ques. 811.—What special provision does this type of 
steam turbine possess for the prevention of accidents in 
case the emergency governor should fail ? 

Ans.—The wheel itself is designed to withstand the 
highest speed, and in addition to this precaution, the en¬ 
tire wheel is encircled by a steel ring which would ef¬ 
fectually prevent the penetration of detached parts. 

Ques. 812.—How may the rotating parts of the 
De Laval Class C Turbine be removed entirely from the 
casing when repairs are necessary ? 

Ans.—By lifting the casing cover, and loosening and 
removing the bearing caps of the shaft. 

Ques. 813.—Why is it possible to maintain indefinite¬ 
ly a high steam economy with this type of steam tur¬ 
bine ? 

Ans.—This is due to the fact that provision is made 
for the easy and quick replacement of those parts sub¬ 
ject to wear. 

Ques. 814.—Is the Type C De Laval Steam Turbine 
built in the larger sizes? 

Ans.—It is not, at present. 

Ques. 815.—Mention some of the principal uses for 
which this turbine is adapted. 

Ans.—It is especially adapted to the driving of cen- 


STEAM TURBINE-FUNDAMENTAL PRINCIPLES 357 

trifugal pumps, blowers, exciters, and small dynamos. 

Ques. 816.—Describe the various conditions of op¬ 
eration for which the Class C Steam Turbine is built. 

Ans.—It may be operated high pressure condensing, 
or high pressure non-condensing. It may also be op¬ 
erated with a certain degree of back pressure. Again, 
it may be operated as a low pressure condensing turbine, 
or it may be operated on mixed flow service. 


EXTRACTS FROM UNITED STATES GOVERN¬ 
MENT RULES FOR THE EXAMINATION 
OF APPLICANTS FOR ENGINEERS’ 

LICENSE. 


I 

i 


Ques. 817.—Give some of the principal regulations 
relative to Marine Engineers. 

Ans.—Before an original license is issued to any per¬ 
son to act as engineer, he must personally appear be¬ 
fore some local board, or a supervising inspector for 
examination; but upon the renewal of such license, 
when the distance from any local board, or supervising 
inspector is such as to put the person holding the same 
to great inconvenience, and expense to appear in person, 
he may upon taking the oath of office before any per¬ 
son authorized to administer oaths, and forwarding the 
same, together with the license to be renewed, to the 
local board, or supervising inspector of the district in 
which he resides, or is employed, have the same renewed 
by the said inspectors, if no valid reason to the contrary 
be known to them, and they shall attach such oath to 
the stub end of the license, which is to be retained on 








358 


QUESTIONS AND ANSWERS 


file in their office. And inspectors are directed, when 
licenses are completed, to draw a broad pen and ink red 
mark through unused spaces in the body thereof, so as 
to prevent as far as possible, illegal interpolation after 
issue. 

Ques. 818.—Give in brief the classification of engi¬ 
neers on the lakes, and seaboard. 

Ans.—The classification of engineers on the lakes, 
and seaboard shall be as follows: 

Chief Engineer. 

First Assistant Engineer. 

Second Assistant Engineer. 

Third Assistant Engineer. 

Ques. 819.—What limitations are placed upon chief 
engineers, and assistant engineers relative to their 
sphere of action? 

Ans.—Inspectors may designate upon the certificate 
of any chief, or assistant engineer the tonnage of the 
vessel on which he may act.” 

Ques. 820.—What additional restrictions are placed 
upon assistant engineers? 

Ans.—First, second, and third assistant engineers 
may act as such on any steamer of the grade of which 
they hold a license, or as such assistant engineer on any 
steamer of a lower grade than those to which they hold 
a license. 

Ques. 821.—On what grades of steamers may assist¬ 
ant engineers act as chief engineers? 

Ans.—Assistant engineers may act as chief engi¬ 
neers on high pressure steamers of one hundred tons bur- 


STEAM TURBINE-FUNDAMENTAL PRINCIPLES 359 


den and under, of the class and tonnage, or particular 
steamer for which the inspectors, after a thorough ex¬ 
amination, may find them qualified. In all cases where 
an assistant engineer is permitted to act as first (chief) 
engineer, the inspector shall state on the face of his cer¬ 
tificate of license, the class and tonnage of steamers, or 
the particular steamer on which he may so act. 

Ques. 822.—What is the duty of an engineer when 
he assumes charge of the boilers and machinery of a 
steamer ? 

Ans.—His duty is to forthwith thoroughly examine 
the same, and if he finds any part thereof in bad con¬ 
dition, caused by neglect or inattention on the part of 
his predecessor, he shall immediately report the facts to 
the local inspectors of the district, who shall thereupon 
investigate the matter, and if the former engineer has 
been culpably derelict of duty, they shall suspend or re- 
voke his license. 

Ques. 823.—What are some of the important require¬ 
ments regarding service that will entitle a person to re¬ 
ceive an original license as engineer or assistant engi¬ 
neer? 

Ans.—He must have served at least three years in 
the engineers’ department of a steam vessel; provided 
that any person who has served as a regular machinist 
in a marine engine works for a period of not less than 
three years; and any person who has served for a period 
of not less than three years as a locomotive engineer, 
stationary engineer, regular machinist in a locomotive, 
or stationary engine works, and any person who has 






360 


QUESTIONS AND ANSWERS 


graduated as a mechanical engineer from a duly recog¬ 
nized school of technology, may be licensed as engineer 
on steam vessels, after having had not less than one 
year’s experience in the engine department of a steam 
vessel. 

Ques. 824.—What are the requirements regarding 
education ? 

Ans.—No original license shall be granted any engi¬ 
neer, or assistant engineer, who cannot read and write, 
and does not understand the plain rules of arithmetic. 

Ques. 825.—What are the requirements regarding 
the age of an applicant? 

Ans.—He must be not less than twenty-one, nor more 
than thirty years of age in order to receive an appoint¬ 
ment as second assistant engineer. 

Ques. 826.—What is the penalty for making a false 
statement before a board of examination, or of produce 
ing a false certificate as to age, time of service or char¬ 
acter ? 

Ans.—Any person found guilty of such action will 
be dropped immediately. 


CHAPTER XI 


MODERN TYPES OF OIL ENGINES 

Ques. 827 .—What is the propelling force behind the 
piston of an oil engine? 

Ans.—The heat energy evolved by the combustion of 
a mixture of vaporized fuel oil and air under compres¬ 
sion. 

Ques. 828 .—How is the vaporization of the oil accom¬ 
plished ? 

Ans.—There are four methods, classified as follows: 

; ( 1 ) Vaporization caused by the heat evolved by the en¬ 
gine. ( 2 ) Vaporization in an external chamber which is 
heated from external sources. ( 3 ) Vaporization in an 
internal chamber heated wholly or in part from external 
1 sources. ( 4 ) Combustion caused by the heat of highly 
compressed air, without previous vaporization of the oil. 

Ques 829 .—Which one of these methods of vaporiza- 
i tion has proved to be the most practicable and best 
adapted to all conditions of service? 

Ans.—The one belonging in class 4 , owing to its sim¬ 
plicity and the absence of much auxiliary equipment, vap¬ 
orization taking place within the cylinder itself. 

Ques. 830 .—Explain the principles of a two-cycle oil 
engine. 

Ans.—A two-cycle engine receives a charge of the 
explosive mixture, compresses it, ignites it and discharges 

the products of combustion while the piston makes one 

361 







362 


QUESTIONS AND ANSWERS 


complete travel backward and forward. Consequently 
it has a working stroke or power impulse for each revo¬ 
lution of the crank shaft. 

Ques. 831 .—Explain the principles of a four-cycle oil 
engine. 

Ans.—The four-cycle engine requires four strokes of 
the piston, or two revolutions of the crank shaft to com¬ 
plete the cycle. Consequently there is but one power im¬ 
pulse for every two revolutions of the crankshaft, or one 
working piston stroke out of four. 1 

Ques. 832 .—Which is the most simple type from a 
constructive point of view? 

Ans.—The four-cycle engine. | 

Ques. 833 .—Give reasons for this. j 

Ans.—The two-cycle engine requires a scavenging air 
pump to discharge the exhaust gases; also special devices 
for the admission of cooling water to the piston. In the 
four-cycle engine this apparatus is not required. 

Ques. 834 .—Which type of engine is the most eco¬ 
nomical in the use of fuel oil? 

Ans.—The fuel consumption per brake horsepower 
of a four-cycle engine is from 7 to 10 per cent less than 
that of the two-cycle engine. 1 

Ques. 835 .—To which one of the four classes of oil 
engines as enumerated in the answer to Question 828 
does the Diesel Engine belong? 

Ans.—To class 4 . 

Ques. 836 .—How is combustion effected in the Diesel 
oil engine? 





MODERN TYPES OF OIL ENGINES 


363 


;ly 


il 


f 

i- 

e 

a; 


r 

3 


a 


r 

i 




Ans.—The Diesel engine admits a large volume of air 
to the cylinder and compresses it to such an extent that 
upon the introduction of oil in the form of spray by a 
blast of air at still higher pressure, combustion occurs at 
once without previous admixture. 

Ques. 837 .—Explain in brief the action taking place 
within the cylinder of a Diesel engine at the beginning of 
a power stroke. 

Ans.—The oil fuel is injected through the fuel valve 
located in the top of the cylinder, which is vertical. This 
valve is opened by a cam just before the piston has 
reached its top center, and the injection of the fuel then 
commences and continues until the piston after passing 
the top dead center has moved through about 10 per cent 
of its downward stroke. Owing to the high pressure now 
prevailing in the combustion chamber, which is that por¬ 
tion of the cylinder space above the piston, a tempera¬ 
ture is produced which exceeds the ignition point of the 
fuel oil, and as a result the oil, having entered the cylin¬ 
der in an extremely pulverized state, is at once ignited, 
and is combusted under approximately constant pressure. 

Ques. 838 .—How is this constant pressure maintained 
during the period of oil admission? 

Ans.—In two ways. First, by the compression pres¬ 
sure exerted by the piston on its up-stroke; second, by the 
admission of compressed air under a pressure exceeding 
that of compression this air is required for the injection 
of the charge of fuel oil. 

Ques. 839 .—What pressure is usually required for 







364 


QUESTIONS AND ANSWERS 


injection of the fuel oil into the combustion chamber of 
an oil engine of the Diesel type? 

Ans.—From 450 to 600 lbs. per sq. in., depending 
upon the style or make of the engine, and also upon local 
conditions. 

Ques. 840 .—From whence is this supply of com¬ 
pressed air obtained ? 

Ans.—From one or more high pressure air compres¬ 
sors usually driven from the main crosshead of the en¬ 
gine by means of links and beams. 

Ques. 841 .—How many working cylinders are there in 
the ordinary Diesel oil engine? 

Ans.—Four, and in some cases six. 

Ques. 842 .—Give a brief description of the construc¬ 
tion and action of the high pressure air compressors al¬ 
ready referred to. 

Ans.—They are of the tandem compound type, two 
or three stage, the low pressure stage being double acting, 
while the intermediate and high pressure stages are single 
acting. Cooling coils are provided for each stage. The 
piston and discharge valves of the low pressure stage are 
of the flat disk type, while those of the higher stages are 
of the poppet type. The high pressure air is delivered to 
a pipe, common to all the cylinders of the engine. This 
pipe conveys the air through separators to the spray-air 
bottle from whence it leads to the fuel inlet valve bodies 
in the cylinder heads. 

Ques. 843 .—What is the function of the spray-air 
bottle ? 


MODERN TYPES OF OIL ENGINES 


365 


Ans.—The spray-air bottle has an overflow valve 
whereby air in excess of that necessary for spraying is 
passed into a bottle for storing the starting air. 

Ques/ 844 .—What is meant by the expression “start¬ 
ing air’’ as used in conection with the Diesel oil engine? 

Ans.—In starting the engine, compressed air at about 
650 lbs. pressure is admitted to those cylinders whose 
cranks are in the proper position for running in the de¬ 
sired direction. After the engine begins to turn, starting 
air is admitted to each cylinder from 10 degrees past the 
top center to 85 degrees past the top center until the en¬ 
gine has attained sufficient speed for fuel admission. 
(These remarks apply to the two-cycle type.) 

Ques. 845 .—Give further details regarding the process 
of starting. 

Ans.—Just before fuel admission occurs clean air 
from the scavenging receiver has been compressed in 
the working cylinders to about 450 lbs. pressure, and 
when the engine is running normally fuel admission to 
each cylinder occurs as follows: When the piston on the 
up stroke is within 2 j 4 degrees of the top center the fuel 
admission valve opens and remains open until the piston 
has reached a point 37 ^ degrees past the top center 
when the valve closes and combustion takes place. 

Ques. 846 .—Describe events in connection with the 
exhaust. 

Ans.—The exhaust ports are uncovered 35 degrees 
before the piston has reached bottom center, and 2 jd 
degrees before the exhaust ports start to be uncovered, 










366 


QUESTIONS AND ANSWERS 


two scavenger valves in the cylinder head are opened by 
the cam shaft, admitting fresh air at 7 or 8 lbs. pressure 
to the cylinder for scavenging. The exhaust ports are 
again covered by the piston at 35 degrees past bottom 
center, and compression begins. 

Ques. 847 .—What length of time do the scavenger 
valves remain open? 

Ans.—Until 31 >4 degrees after the exhaust ports are 
closed bv the piston, from which point compression oc¬ 
curs until 2^2 degrees before the top center is reached, 
when the fuel valve opens as stated in answer to ques¬ 
tion 845 . 

Ques. 848 .—How is the speed of the Diesel oil engine 
regulated ? 

Ans.—By the control of certain factors in connection 
with its operation, as for instance, the amount of fuel 
injected, the amount and pressure of the compressed air 
required for vaporizing and injecting the fuel, also the 
variable admission of fuel by the vaporizer valve in ac¬ 
cordance with the amounts of air and fuel. 

Ques. 849 .—What means are employed for controlling 
the amount of fuel, and the pressure of the injection air? 

Ans.—These factors are adjusted directly from the 
regulator. The air pressure supply is controlled by ad¬ 
justing a slide fitted into the suctions of the low or first 
stage cylinders of the air compressor. The quantity and 
pressure of the spray or injector air is thus easily regu¬ 
lated. The duration of opening of the fuel valve is ad¬ 
justed by the action of the regulator in conjunction with 


MODERN TYPES OF OIL ENGINES 


367 


a pilot valve which is operated by the pressure from one 
of the stages of the air compressor. 

Ques. 850 .—What type of governor is employed to 
effect the above mentioned regulation? 

Ans.—A centrifugal governor, usually of the fly wheel 
1 design. 

Ques. 851 .—Give a brief description of the first two 
Diesel engines built by the United States Government. 

Ans.—These engines constitute the power plant of the 
fuel ship “Maumee.” Each engine will develop 2,500 
horse power at 130 r. p. m. and is of the two-cycle, six 
cylinder, cross head type. The scavenging pumps are 
mounted on the outboard columns of the even numbered 
cylinders and are driven by links and beams from the 
’ main cross heads. Each scavenging pump is double act¬ 
ing and draws the air from both sides of the piston. Di- 
1 rectly under each scavenging compressor, and driven by 
the same cross head, are two water pumps. 

Ques. 852 .—What are the functions of these pumps? 

) Ans.—To supply fresh water for cooling the pistons, 
lubrication for the main crank pin, cross head and thrust 
block bearing; salt water for cooling all the engine parts 
except the pistons; also service for bilge and sanitary 
systems. 

Ques. 853 .—Where are the high pressure air compres¬ 
sors located on these engines? 

Ans.—They are mounted on the outboard columns of 
the odd numbered cylinders, and are driven from the 
main cross head by links and beams. 





368 


QUESTIONS AND ANSWERS 


Ques. 854.—Describe the construction of the bedplate 
and main bearings. 

Ans.—The bed plate consists of three cast iron sec- 
tions bolted together. Each section contains three main 
bearings consisting of a flat bottomed cast iron piece sup¬ 
ported in the bed plate saddle, a lower main bearing brass 
cored for water circulation capable of being rolled out of 
the saddle without removing the crank shaft; and a flat 
topped upper bearing brass. The binding cap is of forged 
steel, and the bearing brasses are lined with a white metal 
consisting of 80 per cent tin, 15 per cent antimony and 5 
per cent copper. 

Ques. 855.—What is the diameter of the crankshaft 
for the engines of the “Maumee?” 

Ans.—15 3/2 inches. It is made of special forgings 
having a tensile strength of 71,000 to 78,000 lbs. and an 
elongation of 18 to 20 per cent. The sections are bored 
hollow and drilled for the forced lubrication system. 

Ques. 856.—Describe the piston rod'. 

Ans.—The piston rod is of forged steel and bored 
hollow for the passage of the fresh water to and from the 
working piston. 

Ques. 857.—Describe in brief the construction of the 
piston. 

Ans.—The piston is divided into two parts, the work¬ 
ing piston, which consists of a specially lined casting cored 
for water circulation and ribbed for strength ; and a lower 
iron casting which is bolted to the piston rod. The two 
sections are not bolted to each other, although both are 



MODERN TYPES OP OIL ENGINES 


369 


secured to the rod. The working piston is dished on top 
and is machined with greater clearance at its top than at 
its bottom. It carries six cast iron snap rings varying in 
width from the top to the bottom, the upper rings being 
given more clearance than the lower ones on account of 
the greater heat. The lower part of the main piston 
merely serves as a guide and is fitted with two cast iron 
snap rings at the bottom. 

Ques. 858.—What is the function of these two snap 
rings ? 

Ans.—To prevent the escape of gas into the engine 
room. 

Ques. 859.—Describe the process of cooling the piston 
while the engine is running. 

Ans.—Fresh water coming up from the rod enters 
the central compartment of the piston, passes out toward 
the side through cored passages at the top and finally 
reaches the concentric space in the piston rod through 
four pipes set at 45 degrees, returning from the highest 
point of the water space, and thus insuring a flow of 
water along the hottest parts of the piston. 

Ques. 860.—What advantage does this system of cool¬ 
ing possess ? 

Ans.—The advantage of simplicity. 

Ques. 861.—What is the disadvantage in connection 
with it? 

Ans.—The disadvantage of heating the water entering 
the piston by that just leaving the piston. 




370 


QUESTIONS AND ANSWERS 


Ques. 862.—Describe the construction of the main 
cylinder. 

Ans.—It is made up of two parts, a cast iron jacket 
carrying the exhaust belt and a plain cylindrical liner of 
special cast iron. The space between the cylinder jacket 
and the liner forms the water jacket for the salt cooling 
water. The top of the liner is securely held in place by 
the cylinder head, while the lower end is free to expand 
through the stuffing box in the bottom of the jacket which 
prevents salt water leakage. The surface of the liner 
passing through the tight fit at the exhaust belt has sev¬ 
eral shallow grooves for the purpose of collecting any 
slight water leakage. These grooves are about 34 inch 
in depth, by y 2 inch in width, and are connected to pet 
cocks on the outside of the jacket. These are kept open 
and serve as leak indicators. 

Ques. 863.—Describe the construction of the cylinder 
head. 

Ans.—The cylinder head is secured to the cylinder 
by 12 studs. The joint between the head and liner is 
made tight by a thin copper gasket. The head has five 
openings to receive the valve cages. The center one is 
for the fuel valve, and the two largest openings on either 
side are for the scavenging valves; the inboard opening 
is for the cylinder release valve, and the outboard open¬ 
ing is for the air starting valve. 

Ques. 864.—How is the cylinder head cooled? 

Ans.—It is divided into two compartments for cool¬ 
ing. The water from the cylinder jacket is by-passed 


■ 

MODERN TYPES OF OIL ENGINES 371 

around the cylinder head joint into the lower compart¬ 
ment of the head through which it must all go before 
rising to the upper compartment. 

Ques. 865.—Describe the fuel spray valve and its 
' operation. 

Ans.—This valve is located in the center of the head. 
It consists of a cast iron body, within which is housed a 
long forged steel needle valve that opens upward. This 
valve is opened by the cam shaft, and is ordinarily held 
i shut by heavy springs. The compressed air for fuel in¬ 
jection is connected to the valve body at the top and 
maintains a constant pressure in the valve body, there 
being a safety valve in the air line at each cylinder. 
Ques. 866.—Where is the camshaft located? 

Ans.—It is located on the inboard side of the engine 
1 and is in four sections. The first section carries the cams 

I for cylinders i and 2; the second the governor, the cam 
for cylinder No. 3 and an eccentric for driving the fuel 
pump for cylinders 1 and 2; the third carries the cam for 
cylinder No. 4 and the gear that transmits the motion of 
, the vertical shaft to the cam shaft which is horizontal; 
i and the fourth carries the cams for cylinders 5 and 6. 

Oues. 867.—Of what does the high pressure air sys¬ 
tem for one engine consist? 

Ans.—It consists of three attached air compressors, 
[ the spray flask of about 5 cubic feet capacity, the six start¬ 
ing-air flasks with a capacity of about 180 cubic feet, air 
separators, piping and release valves. There is also one 
auxiliary air compressor independently driven by steam, 





372 QUESTIONS AND ANSWERS 

with a capacity equal to that of one of the attached air 
compressors. 

Ones. 868.—What is the function of the auxiliary air 
compressor ? 

Ans.—To provide air for charging the spray and start¬ 
ing flasks when all the other air is gone. 

Ques. 869.—Of what does the salt water cooling sys¬ 
tem consist? 

Ans.-—Two attached plunger pumps under the middle 
scavenger pump and an independently driven steam plun¬ 
ger pump, together with the necessary piping and connec¬ 
tion. Both attached pumps have a common suction, and 
each is of sufficient capacity to supply the salt water 
system at normal power. 

Ques. 870.—Describe the course taken by the salt 
water used for cooling. 

Ans.—It is discharged by the pumps into a large main 
at the back of the engine beneath the floor plate. From 
this main a branch leads upward to the bottom of each 
intercooler for the high pressure air compressors and to 
the bottom of each cooler in the scavenger pump cast¬ 
ings. The main then continues around the forward end 
of the engine, where a branch leads upward on the out¬ 
board side of the main bearing cap. Continuing around 
to the inboard side of the engine under the floor plate, 
the main supplies a branch to the bottom of each ahead 
crosshead guide. A collecting main runs around the en¬ 
gine at the height of the cylinder base. On the inboard 
side it receives the return cooling water from the main 


MODERN TYPES OF OIL ENGINES 


373 


bearing and thrust block On the outboard side of the 
engine it receives the cooling water from the scavenger 
cooler. 

Oues. 871.—Describe the further course of the cool¬ 
ing water at the back of the engine. 

Ans.—Back of the engine all the water in the collect¬ 
ing main enters the bottom of the main cylinder jackets, 
two branches leading to each jacket. The cooling water 
leaving the high pressure inter-coolers of each compressor, 
is carried to the lower end of the jacket of the middle 
stage air compressor cylinder, from whence it is forced 
Tip ward into the jacket of the low stage cylinder through 
two ferrules set partly into each cylinder at the joint. 
From the low stage jacket, the water enters the high stage 
jacket through two bv-presses around the cylinder joint, 
and from the high stage jacket the water is forced into 
the high stage cylinder head to two by-passes around the 
joint between the head and cylinder. From the head of 
each high stage cylinder the water is led into the exhaust 
pipe jacket and from here is finally discharged into an 
overboard discharge main. 

Oues. 872.—How is the fresh cooling water carried 
to the piston? 

Ans.—Fresh cooling water is drawn from a compart¬ 
ment in the double bottom, where it is cooled, to the piston 
through a swivel joint on the after beam bearing, a pipe 
secured to the beam, another swivel joint on the cross¬ 
head end of the beam, the main crosshead, a nickle-steel 
pipe running up through the center of the piston rod, and 







374 


QUESTIONS AND ANSWERS 


four collecting pipes reaching the highest part of the 
outer cooling space in the piston, and from thence return¬ 
ing through the concentric space in the piston rod, it 
finally reaches a discharge main back of the engine via 
links and beams and the forward end of the crosshead in 
a manner similar to that by which it entered. 

Oues. 873.—Describe the facilities for maneuvering 
the engine. 

Ans.—On the operator’s platform is the maneuvering 
control wheel, which controls the starting, stopping and 
reversal of the engine by means of compressed air. This 
wheel also cuts off the fuel and spray air from the cylin¬ 
ders during maneuvering and until the engine is turning 
over in the desired direction. Above the maneuvering 
control is a dial on which a pointer indicates the running 
position of the engine. There is also a hand cutout by 
which die engine can be instantly stopped. It operates to 
raise the suction valves of the fuel pumps thus rendering 
them inoperative. 

Oues. 874.—What other facilities are provided for 
hand control? 

Ans.—A fuel control wheel by means of which the 
quantity of fuel pumped into each cylinder may be con¬ 
trolled. A dial and pointer above the fuel control indi¬ 
cate in eight equal steps the quantity of fuel pumped, 
from a minimum to the maximum. Coming out from the 
shaft of the fuel control wheel is the needle stroke con¬ 
trol which varies the stroke of the fuel spray needle from 
maximum to minimum. There is also a hand control for 










MODERN TYPES OF OIL ENGINES 375 

the high pressure air which regulates the opening of the 
suctions of the low stage cylinders of the air compres¬ 
sors. The quantity and pressure of the spray air is thus 
controlled. 

Ques. 875.—What kind of oil is used in engines of 
the Diesel type? 

Ans.—Crude petroleum having a heat value of 18,000 
to 20,000 b. t. u. per pound. 

Ques. 876.—How does fuel oil compare with coal in 
heat value ? 

Ans.—To compare the fuel consumption per brake 
horse power of an oil engine with that of a steam engine 
one pound of oil may be considered as equivalent to Ij4 
lbs. of coal. 

Ques. 877.—What is the usual rate of fuel oil con¬ 
sumption per brake horse-power-hour for oil engines? 

Ans.—Recent tests of a 500 horse power engine of 
the Diesel type show an average oil consumption of 0.483 
lbs. of oil per brake horse-power-hour. 

Ques. 878.—Did the load on the engine vary to any 
extent during the course of these tests ? 

Ans.—It varied from 25 per cent below, to 113 per 
cent above normal rating. 

Ques. 879.—Regarding efficiency, what can be said 
of the Diesel type oil engine? 

Ans.—It gives a high efficiency in service, in fact is 
said to be one of the most efficient prime movers known 
at present (1917). 






376 


QUESTIONS AND ANSWERS 


Ones. 880.—Is auxiliary ignition apparatus required 
in the Diesel engine? 

Ans.—It is not. The fuel oil is ignited by the tem¬ 
perature of compression. This fuel does not explode as 
in a gasoline engine, but burns in the cylinder, and by ‘ 
the heating and expansion of the air and gases within j 
the cylinder, the piston is forced out on its working stroke. 

Ques. 881.—What other type of oil engine resembles 
the Diesel engine in the process of ignition? 

Ans.—The Hornsby-Ackroyd Engine. In this engine 
the oil is first introduced into a vaporizer located at the 
back or side of the cylinder, the heat necessary for vapor¬ 
ization being supplied at starting by external lamps, but 
when the engine is in operation the continued combustion 
of the fuel supplies sufficient heat for both vaporization 
and ignition. 

Ques. 882.—How is the air necessary for combustion 
introduced into the cylinder? 

Ans.—This being a four-cycle engine, air enters the 
cylinder during the suction period of the cycle. Thus the 
cylinder becomes charged with air, and the vaporizer 
becomes filled with a spray of oil simultaneously. Dur¬ 
ing the compression period the air in the cylinder, being 
forced into the vaporizer, becomes properly mixed with 
the oil and an explosive mixture is formed. 

Ques. 883.—How is the oil fuel supplied to the 
Hornsby-Ackroyd engine ? 

Ans.—By an oil pump, the stroke of which is under 










MODERN TYPES OF OIL ENGINES 


377 


control of the governor, thus giving close regulation of 
speed. This engine is built either horizontal or vertical. 

Ques. 884.—Describe some of the peculiar features of 
the Remington Oil Engine. 

Ans.—This engine is valveless, the gases being moved 
into and out of the cylinder through ports uncovered by 
the movement of piston, which itself also performs the 
function of a pump. 

Ques. 885.—How does this action take place? 

Ans.—The engine is of the vertical type, operating 
on the two-stroke cycle. On the up-stroke of the piston 
a partial vacuum is created in the enclosed crankcase, and 
when the bottom of the piston uncovers the inlet port 
which is directly under the exhaust port, the air rushes 
in and fills the crankcase at atmospheric pressure. On 
the next down stroke this air is compressed in the crank 
case to four or five pounds pressure; while at the same 
time the mixture of oil-vapor and air already in the cylin¬ 
der is burning and expanding, thus forcing the piston 
down on its working stroke. When the piston approaches 
the end of its down stroke it uncovers the exhaust port 
on the side of the cylinder, permitting the burnt charge 
to escape to the atmosphere. Immediately after this event 
Stakes place the transfer port on the opposite side of the 
I cylinder is uncovered by the piston, thus allowing a por¬ 
tion of the air compressed in the crank case to pass into 
the cylinder, where it is deflected upwards by the shape of 
the piston, and caused to fill the cylinder, thereby expell¬ 
ing the remainder of the burnt charge. The piston now 







378 


QUESTIONS AND ANSWERS 


starts on another up-stroke, compressing the fresh charge 
of air into the hot cylinder head. 

Ques. 886.—How is the fuel oil admitted to the 
cylinder ? 

Ans.—When the piston is near the end of the upward 
compression stroke, an oil pump mounted on the crank¬ 
case and controlled by the governor injects the proper 
amount of oil through the nozzle into the space above the 
piston now occupied by the compressed and heated air. 
This oil is atomized in a vertical direction through an 
opening near the end of the nozzle, and is thus vaporized 
and gasified before it reaches the cylinder walls. 

Ques. 887.—How is ignition effected in the Remington 
oil engine? 

Ans.—By means of a nickel steel plug located in the 
center of the cylinder head, and kept red hot by the ex¬ 
plosions. By the burning of the oil spray in the com¬ 
pressed air the pressure is increased and the piston is 
now forced downward on its power stroke. 

Ques. 888.—Of what type is the Remington oil en¬ 
gine ? 

Ans.—It is a two-cycle engine, since the operations 
hitherto described take place with every revolution of the 
crank shaft. Therefore each down stroke is a power 
stroke. 

Several sizes of this engine are built especially to 
operate on semi-refined fuels, such as distillate, solar oil, 
gas oil, etc. All sizes of Remington oil engines are built 
to operate on all grades of ordinary kerosene oil. 










MODERN TYPES OF OIL ENGINES 


379 


Ques. 889.—Does the use of kerosene and other distil¬ 
lates of petroleum as fuel for internal combustion engines 
give satisfactory results? 

Ans.—It does, provided the engine has been designed 
for using that grade of fuels. 

Ques. 890.—What are the principal characteristics of 
the Nordberg high compression oil engine? 

Ans.—This engine ignites its fuel of its own compres¬ 
sion. It therefore requires no hot bulb, torch, or other 
auxiliary ignition device. It has no valve gear or valves 
subject to the working pressure and heat, there being but 
one valve on the engine and it is located at a point where 
it is not affected by the heat. It operates its own fuel 
pump by means of an eccentric on the crank shaft. 

Ques. 891.—Of what type is the Nordberg engine? 

Ans.—It is of the two-cycle type. 

Ques. 892.—Describe the operations of the exhaust, 
and the admission of the scavenging air to the cylinder. 

Ans.—Near the end of the working stroke the piston 
uncovers the exhaust ports, and after these have been 
opened a certain amount, the scavenging port is also un¬ 
covered by the piston and fresh air from the scavenging 
space is blown into the cylinder and through the exhaust 
openings, thus cleaning out the burned gases and provid¬ 
ing fresh air for the next cycle. 

Ques. 893.—Describe the processes of compression 
and ignition in this engine. 

Ans.—With the piston on the return stroke, the air 
entrapped in the cylinder is compressed to a pressure of 







380 


QUESTIONS AND ANSWERS 


approximately 450 pounds, and at the end of the stroke, 
fuel oil is injected through the fuel nozzle located in the 
cylinder head, and ignition occurs, due to the heat of 
the compressed air. 

Ques 894.—How is this fuel supplied to the nozzle 
under the required pressure? 

Ans.—By the fuel pump driven by an eccentric on the 
crank shaft. 

Ques. 895.—How is the quantity of fuel oil required 
by the engine controlled in order to maintain a uniform 
speed at varying loads ? 

Ans.—By means of a centrifugal shaft governor which 
acts on the fuel pump through a rod, and determines the 
amount of oil which is by-passed by the pump, that is, 
the amount not used. 

Ques. 896.—Describe the construction of the fuel 
pump and appurtenances. 

Ans.—This oil pump is a simple plunger pump, of a 
very strong construction. The plunger receives its mo¬ 
tion from a driving cam operated by an eccentric on the 
crank shaft. The plunger has a constant stroke, and the 
capacity of the pump is for a much greater quantity of 
oil than the engine would ever use, but as before stated, 
the amount of oil actually pumped to the fuel nozzle is 
always under the control of the shaft governor. The fuel 
pump and driving cam are located in a cast iron box kept 
filled with oil, so that the pump operating mechanism is 
continually submerged in this oil. 




MODERN TYPES OF OIL ENGINES 381 

Ques. 897. How is the Nordberg oil engine started? 

Ans. By means of compressed air at a pressure of 
250 pounds admitted to the cylinder, behind the piston. 

Ques. 898.—Describe the starting valve, and its opera¬ 
tion. 

A n s. The starting valve is of the quick opening type, 
and is manipulated by the operator who gives the cylinder 
the proper charge of compressed air for the right portion 
of the stroke. After one or two revolutions the operator 
starts the fuel pump by means of a lever which throws 
the pump cam into connection, thus starting the flow of 
fuel oil to the cylinder. The engine usually fires on the 
third or fourth revolution. 

Ques. 899.—How is compressed air at 250 pounds 
pressure supplied to the engine for starting? 

Ans.—From a welded steel storage tank kept charged 
by means of a two-stage air compressor furnished with 
the engine. This air compressor is designed for a work¬ 
ing pressure of 250 pounds, and is provided with an inter¬ 
cooler. It may be driven by a belt from the engine, or 
from a motor or line shaft. 

Ques. 900.—Does this compressor run continuously? 

Ans.—It does not. It is used only for short periods 
when recharging the air-storage tank after the oil engine 
has been put in operation. 

Ques. 901.—Flow is the scavenging air supplied to the 
cylinder ? 

Ans.—The space between the piston and the front end 
of the cylinder is used as a compression space. On the 









382 


QUESTIONS AND ANSWERS 


back stroke of the piston, air is drawn into this space 
through a piston valve driven by an eccentric on the main 
crank shaft. On the forward stroke of the piston this air 
is slightly compressed in the space between cylinder head 
and piston, until at the end of the stroke, the scavenging 
port is opened by the piston, as already described. 

Ques. 902.—Describe the action of the fuel nozzle. 

Ans.—The fuel nozzle atomizes the fuel oil by direct 
mechanical pressure from the fuel pump; and not by 
means of highly compressed air. 

Ques. 903.—What types of fuel oil can be used in 
the Nordberg oil engine? 

Ans.—The leading types, such as regular fuel oil, 
kerosene, and other distillate. 

Ques. 904.—Describe the method of providing the 
required storage for this fuel. 

Ans.—A reservoir fitted with compartments for the 
different types of fuel oil is provided. This reservoir is 
kept supplied with fuel oil by means of a small pump 
driven from the engine. This pump lifts the fuel oil from 
the underground storage tank, and delivers it into the 
reservoir which stands at a level sufficiently high to allow 
the fuel oil to run by gravity to the fuel pump on the en¬ 
gine. The overflow from this fuel reservoir can be piped 
back to the underground tank. 

Ques. 905.—At what times is kerosene or distillate 
used as fuel on this engine? 

Ans.—Usually in starting, when the regular fuel oil 
is heavy or viscous. 


MODERN TYPES OF OIL ENGINES 


383 


Ques. 906.—What changes are required in order to 
change from distillate to the regular fuel, or vice versa? 

Ans.—It is necessary only to turn a three-way cock. 

Ques. 907.—How is the cylinder cooled? 

Ans.—It is water jacketed, and the jacket spaces are 
provided with hand-holes for cleaning. 

Ques. 908.—What quantity of water is required for 
cooling? 

Ans.—From four to seven gallons per brake horse 
power hour, depending upon the temperature of the 
water. 

Ques. 909.—Is the Nordberg oil engine equipped with 
a cross-head? 

Ans.—It is provided with a cross-head running in 
bored guides. 

Ques. 910.—Of what type is the Lawson kerosene 
engine ? 

Ans.—It is of the vertical, four-cylinder type: de¬ 
signed primarily to operate on kerosene, although it may 
be operated on power distillate, or gasoline. 

Ques. 911.—How is the fuel for this engine admitted 
to the cylinders? 

Ans.—By means of inlet poppet valves, located in the 
cylinder heads. These valves are operated by overhead 
tappets which receive their motion from a cam-shaft. 

Ques. 912.—How are the products of combustion ex¬ 
hausted from the cylinders? 

Ans.—By means of exhaust valves also located in the 
cylinder heads, and operated by the same cam-shaft. 







384 


QUESTIONS AND ANSWERS 


Ques. 913.—Describe the fuel feeding device in use 
on the Lawson kerosene engine. 

Ans.—It is of the venturi atomizer type, the function 
of which is to maintain a uniformly high velocity of air 
through a venturi tube having radial holes in its restricted 
portion through which the fuel is admitted by suction. 

Ques. 914.—How is the speed of this engine con¬ 
trolled ? 

Ans.—By means of a fly-ball governor, driven from a 
bevel gear pn the cam-shaft, and acting to control the ad- j 
mission of fuel to the cylinder. The governor acts di¬ 
rectly upon a two-ported barrel valve whose ports coincide 
with the ports in the valve housing when the engine is at 
rest. When the engine has attained full speed the barrel 
valve is rotated by the governor, thereby closing the lower 
port and decreasing the amount of fuel and air admitted 
into the cylinder. At the same time the upper port is 
also closed, deflecting more air through the nozzle and 
maintaining practically a constant velocity of air at this 
point. 

Ques. 915.—How is adjustment made for no load and 
full load? ! 

Ans.—By means of a fuel needle valve, in conjunc¬ 
tion with a butterfly valve in the air inlet. 

Ques. 916.—Is each cylinder equipped with a fuel 
feeding device such as described? 

Ans.—A separate carburetor, or atomizer as it is 
called, is provided for each cylinder, in order to prevent 
liquefying of the fuel before it reaches the cylinder. 




MODERN TYPES OF OIL ENGINES 


385 


Ques. 917.—What provision is made to prevent pre¬ 
mature ignition on full load? 

Ans.—A water feed is provided for this purpose. 

Ques. 918.—Describe the cooling system in use on 
the Lawson engine. 

Ans.—The cylinders and cylinder heads are water 
jacketed. The heads carry the valves which seat directly 
against the water jacket, thereby bringing the water as 
close as possible to the valve heads, and thus prevent 
undue heating of the same, which is exceedingly detri¬ 
mental in a kerosene engine. 

Ques. 919.—What kind of piston is in use on this 
engine ? 

Ans.—The pistons are of the barrel or trunk type, 
each piston being equipped with four rings, three on its 
extreme upper end, and one on its extreme lower end. 

Ques. 920.—Describe the valve operating mechanism. 

Ans.—The cam-shaft is carried in five bronze bear¬ 
ings within the crank-case. The cams for each cylinder, 
viz., exhaust, inlet and igniter, are integral, and keyed 
to the cam-shaft. The push-rods acting upon the valve 
tappets are provided with hardened slides which are fitted 
with rollers for contact with the cams. The tappet 
levers are adjustable for wear. 

Ques. 921.—How is cooling water supplied to the 
Lawson kerosene engine? 

Ans.—By means of a circulating pump mounted on 
the engine, and driven directly from the crank-shaft 
through the medium of a chain and sprocket gear. 








386 


QUESTIONS AND ANSWERS 


Ques. 922.—Describe the course of the water in its 
circulation through the jacket? 

Ans.—Water is admitted to the cylinder jacket on 
one side, directly in line with the lower line of the com¬ 
pression chamber, the cooling water not passing directly 
through the lower portion of the jacket, owing to the 
fact that the exhaust water is taken out of the top of 
the head by means of a polished brass manifold which 
is provided with expansion joints to avoid cracking. 

Ques. 923.—What system of ignition is used on this 
engine ? 

Ans.—The ignition is of the standard make and break 
type, and is arranged with two timing adjustments, one 
individual, and one simultaneous. The latter adjust¬ 
ment is used in starting, and is so arranged that all 
igniters may be stopped by shifting the timing lever. 
Directly over the igniter is mounted an insulated brass 
bar which is charged with current from a gear-driven 
magneto, alternating current. The igniters are provided 
with a spring coming in contact with this brass bar, thus 
eliminating wiring connection. 

Ques. 924.—How is the engine started? 

Ans.—An air starter is used which admits air into 
each cylinder through an automatic air valve in the head. 
As soon as the engine fires, the pressure within the 
cylinder holds this valve in its seat, thereby preventing 
admission of air. The starter consists of a main body, 
having four radial air ports connected by piping to the 
different cylinders. These ports are covered, and un- 





MODERN TYPES OF OIL ENGINES 


387 


covered by a rotary disc valve having one port. This 
disc is held on its seat by the pressure of the air and 
is free to rotate when the air is shut off. The starter 
is connected to the end of the cam-shaft by means of 
a flexibld coupling. To start the engine, all that is 
necessary is to turn it on the center and open the air 
cock, no shifting of cams and gears being required. 

Ques. 925.—What kind of fuel is used in starting? 

Ans.—Gasoline is used until the engine has attained 
full speed, when it may be turned over until it runs on 
kerosene. 










INDEX 


A 


Absolute pressure. 

Absolute zero. 

Adiabatic curve . 

Admission— 

Instant of .. 

Air— 

Admission to furnace.. 

Advantage in heating. 

Composition of. 

Locks, object of. 

Product of. 

Volume required for combustion 
Air pump— 

Description of. 

Dimensions of. . . 

Types of. 

Valves for.. 

Angular advance. 

Apparatus— 

Condensing, for steam turbines.. 
Ash— 

Dry . 

Ash ejector. 

Ash pits— 

Closed . 


PAGL 
... 286 
... 288 
290-303 

... 188 

... 8-5 
... 131 
... 17 

124-126 
... 18 
..17-19 


225-226 
... 218 
224-225 
... 227 
... 191 

... 338 

... 144 
... 127 

... 123 


B 

Blow-off— 

Surface .. 112 

Bottom . 113 

Boilers— 

Bracing . 66 

Back arch for horizontal tubular.82-83 




































INDEX 


PAGE 

Connecting up.138-139 

Feed pump. 97 

Heating surface. 86-87 

Horsepower .86-87 

Leaks ... 135 

Marine . 1(39 

Material . 65 

Operation . 128 

Rivets . 66 

Seams, welded. 76 

Steam space of. 110 

Types of.25-64 

Washing out.134-136 

Boiler construction. 65 

Boyles law.14, 290 

Braces . 66 

Bucket speed . 304 

Bursting pressure. 77 

C 

Calorimeter . 145 

Carbon . 17 

Carbon, monoxide . 21 

Clearance . 302 

Piston .r. 289 

Steam . 289 

Coal- 

Composition of. 22 

Consumption of. 156 

Dry . 145 

Heating value of one pound. 24 

Method of ascertaining cost.154-155 

Moisture in . 145 

Cocks— 

Asbestos packed. 117 

Gauge . 104 

Hydrometer . 114 

Combustible— 

Weight of. 145 

Combustion . 17 












































INDEX 


PAGE 

Rate of. 20 

Compression . 302 

Advantage of. 189 

Instant of. 188 

Meaning of. 289 

Condensation .233-235 

Cylinder . 293 

Condenser— 

Advantages in use of.214-215 

For steam turbines. 338 

Jet . 217 

Siphon . 216 

Surface . 213 

Corrosion . 168 

Cause of. 169 

Prevention of. 170 

Curves— 

Adiabatic .290-303 

Expansion . 290 

Isothermal . 290 

Cut-off— 

Adjustable . 295 

Fixed . 295 

Instant of. 188 

D 

Dampers— 

Funnel .117-118 

Dead-center .202-208 

Diagram— 

Characteristics of. 296 

Details of.285-286 

Method of taking.284-285 

Distillers .253-254 

Draught . 19 

Artificial .19-122 

Essentials for. 150 

Forced . 122-124 

Measuring .150-151 

Natural .19, 122 



































INDEX 


Systems . 

Draught gauge .. 

Dry-pipe . 

Dynamics . 

Dynamos— 

For marine service 


PAGE 

131-132 
... 150 
... 112 
... 291 

260-264 


E 

Eccentric— 

Description of. 190 

Position .191-204 

Throw of. 191 

Efficiency— 

Plant . 292 

Steam . 291 

Ejector— 

Ash . 127 

Engine— 

Automatic .294 

Classes of.173-178 

Four-valve . 185 

Marine . 192 

Variable cut-off .;. 294 

Evaporation— 

Equivalent . 152 

Factor of.153-154 

Of water. 152 

Evaporation tests— 

Apparatus for. 141 

Data for . 148 

Duration of. 148 

Method of conducting. 141 

Objects of.t. 140 

Preparing for.146-147 

Evaporators— 

For marine service.253-254 

Exhaust steam— 

Disposal of . 337 

Expansion . 13 

Advantages of. 179 





































INDEX 


PAGE 

Curve . 290 

Joint . 116 

Rate of.•. 181 

Ratio of. 288 

F 

Feed pumps. 97 

Feed water— 

Average temperature of.145-146 

Heaters . 247-248 

How supplied to boiler. 139 

Stoppage of supply. 140 

Fire cleaning . 129 

Firing— 

Hand . 130 

Fire-main . 269 

Fire tools. 128 

Foot pound. 290 

Force . 291 

Forced draught'.122-124 

Friction— 

In steam turbines. 341 

Fuels . 167 

Funnel-stays . 119 

Funnel cover .121-122 

Furnace— 

Corrugated .26- 78 

Petroleum . 165 

Temperature of. 21 

Fusible plug.106-107 

G 

Galvanic action. 170 

Cause of. 170 

Prevention of. 171 

Gases— 

Escaping . 146 

Gauge— 

Cock . 104 

Steam .107-110 



































INDEX 


Governor— pace 

Adjustment of.209-210 

Curtis steam turbine. 321 

Dunlop’s . 250-253 

Inertia .204-205 

Isochronal .204-295 

Marine . 250 

Object of. 249 

Principle of. 249 

Shaft . 295 

Throttling . 294 

Grate-bars— 

Dimensions of.;. 84 

Types of.85-86 

Grate-surface .84-85 

Grease filters. 249 

H 

Hand firing. 130 

Disadvantages of. 156 

Heat— 

Latent . 15 

Loss of. 131 

Mechanical equivalent of....: . 16 

Radiation of. 16 

Sensible . 15 

Specific . 14 

Transmission of. 16 

Horsepower— 

Boiler . 155 

Constant . 289 

Engine . 289 

Indicated . 289 

Net .289 

Hot-well .228-229 

' - - ^ 


Hydrometer . 

Hydrometer cock. 114 

I 

Indicator— 

Care of.282-283 

Construction of.272-273 









































INDEX 


PAGE 

Diagram .276-277 

Principles of. 271 

Injector— 

Principles of. 101 

Isothermal curve. 290 

J 

Jet condenser. 217 

Jet speed. 304 

L 

Lap . 187 

Inside . 188 

Outside . 188 

Latent heat . 15 

Lead . 188 

Decreasing . 203 

Equalizing . 203 

Object of. 189 

Lighting- 

In marine service.265-266 

Link- 

Block . 195 

Curvature of. 194 

Slip of. 195 

Link-motion . 192 

Locks— 

Air .124-126 

M 

Mean effective pressure.287-297 

Method of finding. 299 

Mechanical stokers . 157 

Types of.157-161 

Moisture— 

In coal.145-152 

In steam. 145 

Momentum . 291 

Motion— 

F’rst law of 


290 

































INDEX 


o 

Oil— page 

Composition of. 24 

Engines. 361 

Fuel . 24 

Heating value of. 24 

Ordinates . 293 

Oxidation. 169 

I P 

Petroleum— 

Advantages in use of.166-167 

Analysis of. 164 

Heating value of. 165 

Method of inducting to furnace. 166 

Objection to. 167 

Piston— 

Balancing . 202 

Piston clearance.’ 289 

Piston displacement . 289 

Piston speed. 289 

Plaximeter .300-301 

Plates— 

Oxidation of. 169 

Power— 

Definition . 290 

Pressure— 

Absolute. 286 

Absolute back. 287 

Back . 287 

Boiler . 286 

Bursting . 77 

Condenser . 288 

Expansion of. 13 

Gauge . 286 

Initial . 286 

Mean effective. 287 

Safe working. 77 

Terminal .286-287 

Pumps— 

Air . 215 

Bilge .266-267 







































INDEX 


Boiler feed. 

Centrifugal . 

Circulating . 

Double acting. 

Dry air. 

Duplex . 

Fire, marine.. 

For marine service 

Location of. 

Petroleum . 


PAGE 


241 


231 1 


... 230 
242-246 
... 339 
... 97 
267-268 
... 240 
... 241 
... 166 


R 

Ratio— 

Of cylinder volumes. 179 

Receiver .179-180 

Reducing motion. 280 

Reducing wheel..'.279 

Re-evaporation— 

Cylinder . 293 

Refrigeration— 

Cold air system.255-258 

Carbonic acid system.259-260 

Release— 

Instant of. 188 

Rivets— 

Material for. 66 

Test for. 66 

Riveted joints— 

Efficiency of.72-74 

Lloyd’s rules for. 75 

Rocker arm— 

Adjustment of.206 

Rules— 

For finding heating surface of various types of boilers. .87-89 

For finding heating surface of corrugated flues. 90 

For finding area of lever safety valves. 93 

For finding speed of pump. 98 

For finding velocity of flow in discharge pipe.98-99 

For finding required size of feed pump.1100-101 

For finding boiler horsepower... 156 































INDEX 


PAGK 

For finding weight of condensing water.234-235 

Rules— 

For finding I. H. P.301 

For finding bursting pressure. 77 

For finding safe working pressure. 77 

S 

Safe working pressure. 77 

Safety valve— 

Duty of . 90 

( Types of.91-92 

Scale . 137 

Sea water.. 170 

Composition of. 211 

Disadvantages in using. 212 

Sensible heat.•. 15 

Separator .116-118 

Siphon condenser.,.216 

Siren, steam.112-113 

Smoke and soot. 21 

Specific heat. 14 

Speed— 

Bucket ... 304 

Jet .304 

Piston . 289 

Regulation in Curtis turbine. 321 

Regulation in Hamilton-Holzworth turbine.335-336 

Steam .304 

Stays— 

Gusset . 67 

Funnel ... 119 

Material for. 67-68 

Stay bolts.71-72 

Steam . 7 

Action of in engine cylinder.... 173 

Clearance . 289 

Consumption per H. P. hour. 292 

Dry . 145 

Gauge . 197 

Maximum theoretical duty of. 291 

Moisture in. 14 <j 









































INDEX 


PAGE 

Physical properties of. 8-12 

Relative volume of. 7 j 

Theoretical velocity of. 305 

Volume of. 7 

Wire drawn. 288 

Steam efficiency. 291 

Steam gauge.107-110 

Steam siren.112-113 

Steam speed.304 

Steam turbine— 

Action of steam in.304 

Advantage over reciprocating engine.305-306, 322-340 

Allis-Chalmers . 342 

Curtis (descriptive) .314-321 

De Laval (descriptive).306-314 

Friction in. 341 

Hamilton-Holzworth .330-337 

Principles of. 304 

Westinghouse-Parsons .323-330 

Stoke-hold— 

Closed .126-127 

Stokers— 

For marine service. 164 

Fuel for. 164 

Mechanical . 157 

Method of supplying coal to.163-164 

Underfeed .162-163 

Surface condenser— 

Advantages of. 213 

Construction and action of. 219 

Tubes of.221-2*22 


T 

Tables— 

Analysis of coal. 23 

Areas and circumferences of circles.237-238 

Capacities and speed of De Laval turbines. 314 

Diameters of rivets.. 73 

Factors of evaporation. 155 

Lap and lead of Corliss valves. 209 

Physical properties of saturated steam.8-12 





































INDEX 


PAGE 

Proportion of triple riveted butt joints. 7C 

^ Specific heat of various substances.14-15 

Water required for jet condensers. 235 

Weight of water at various temperatures. 144 

Tests— 

Evaporation . 140 

For efficiency of boiler.149-152 

Test piece.65-66 

Thermal unit. 16 

Thermo-dynamics .*.... 15 

Thermometer— 

Hot water. 146 

Tubes— 

Cleaning .133-137 

Fire . 25 

Galloway . 37 

Material for. 66 

Submerged . 25 

Water . 25 

Working test for.-66 

Turbines— 

Action of steam in. 304 

Advantage over reciprocating engine....305-306, 322-340 

Allis-Chalmers . 342 

Curtis (descriptive) .306-314 

De Laval (descriptive).314-321 

Friction in. 341 

Hamilton-Holzworth .330-337 

Principles of. 304 

Westinghouse-Parsons .323-330 

V 

Vacuum— 

How measured. 213 

How maintained.215-219 

In turbine condensers.340 

Meaning of. 213 

Perfect .287 

Vacuum gauge— 

Mercurial .214 

.Spring . 214 







































INDEX 

m 

Valves— 

Check . 

Double-ported . 

Piston . 

Poppet . 

Treble-ported . 

Safety . 

Setting . 

Sea ... 

Slide . 

Steam stop. 

Steam stop, automatic. 

Valve gear— 

Joy ... 

Marshall . 

Reversing . 

Valve-setting . 

Defects in. 

W 

Water— 

Evaporation per pound of coal... 

Sea. ... 

Quantity required for condenser.. 

Water column. 

Whistle— 

Steam . 

Wire drawing. 

Wood— 

Composition of. 

Disadvantage of as fuel. 

Heating value of, in thermal units 
Work— 

Definition of. 

Unit of. 

Wrist-plate— 

Vibration of 

Zero— 

Absolute ... 

Zinc slabs. 




iap 

200 

90 


202-205 
... 239 
186-187 
... 110 
... -Ml 

... 196 
... 195 
194-195 
202-205 
... 297 


... 152 
170-211 
... 233 
105-106 

111-112 

288-297 

... 24 
... 24 
... 24 

... 291 
... 290 

... 207 


... 288 
171-172 













































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